The Z Files: The Necessary Evil of Park Factors

The Z Files: The Necessary Evil of Park Factors

This article is part of our The Z Files series.

Playing matchups is an integral aspect of fantasy baseball, be it seasonal or DFS play. One of the key components of matchup analysis is understanding park factors. Today we're going to address some of the misconceptions with respect to park factors, followed by a comprehensive review of all 30 parks. But first, let's review the concept in general.

A neutral park factor is denoted as 100. Anything over 100 favors that metric while a number under 100 depresses it. For example, a 110 home run factor increases long balls by 10 percent over a neutral park while an 88 run factor reduces runs by 12 percent as compared to a neutral venue.

Park factors exist for every stat, not just runs, hits and homers. Often overlooked is the fact that strikeouts and walks are influenced by the venue. Yards with a lot of foul territory depress strikeouts, since a foul pop reaching the stands is a strike in most parks, but an out in places like the Oakland-Alameda County Coliseum. Some venues also have a better or worse batting eye (the center field background).

However, there's one big myth concerning park factors that needs to be addressed first:

1. The quality of the team's offense or pitching influences the park factor

Honesty, it boggles my mind how some that quote park factors in their analysis allude to how it's affected by the quality of the team. The conventional formula is designed to flesh out the bias associated with how well

Playing matchups is an integral aspect of fantasy baseball, be it seasonal or DFS play. One of the key components of matchup analysis is understanding park factors. Today we're going to address some of the misconceptions with respect to park factors, followed by a comprehensive review of all 30 parks. But first, let's review the concept in general.

A neutral park factor is denoted as 100. Anything over 100 favors that metric while a number under 100 depresses it. For example, a 110 home run factor increases long balls by 10 percent over a neutral park while an 88 run factor reduces runs by 12 percent as compared to a neutral venue.

Park factors exist for every stat, not just runs, hits and homers. Often overlooked is the fact that strikeouts and walks are influenced by the venue. Yards with a lot of foul territory depress strikeouts, since a foul pop reaching the stands is a strike in most parks, but an out in places like the Oakland-Alameda County Coliseum. Some venues also have a better or worse batting eye (the center field background).

However, there's one big myth concerning park factors that needs to be addressed first:

1. The quality of the team's offense or pitching influences the park factor

Honesty, it boggles my mind how some that quote park factors in their analysis allude to how it's affected by the quality of the team. The conventional formula is designed to flesh out the bias associated with how well or poorly the home team's hitters and pitchers perform. On paper, the venue is independent of the strength or weakness of the lineup or staff. A great offense can score in a pitcher's park while a bad offense may not score many runs, even in a hitter's venue.

That then leads to another critique:

2. The conventional formula removes some, but not all the bias

This argument is not just that the formula fails to account for all bias from the home team's roster. It's also that the formula fails to completely flesh out variance.

First, the bias. While the formula attempts to deal with quality of the home team by comparing the hitter's and hurler's performance home and away, some teams can be built to take advantage of their home venue's quirks. As an extreme example, let's say the Boston Red Sox have a bunch of lefties that are dead pull hitters - and I mean everything goes right down the right-field line. People always talk about the proximity of the Green Monster, but the Pesky Pole is a mere 302 feet from the batter's box. In our hyperbolic example, Red Sox hitters ping homers off Pesky's Pole with regularity while the opposing squad's lefty swingers have their fly balls caught in the deepest right field in the league. In this scenario, the left-handed batter home run factor would be well over 100, whereas in reality it's 75. Of course, the Bostonians don't have that mythical lineup of dead pull hitters, but this example shows how teams can have an advantage if some element of their team, be it offense, pitching, defense or handedness, meshes well with their home park.

Using another example, the sample of left-handed pitchers is smaller than righty tossers. If every southpaw a team faces at home is a stud, while every lefty it faces on the road is a dud, the performance of right-handed hitters will be disproportionately worse at home, negatively impact the factor, especially for right-handed hitters. Obviously, the home/away mix of opposing lefties taking the hill is closer to equal, but so long as it isn't 50/50, there's some residual bias.

Chances are, after reading, "fails to completely flesh out variance" above, many of you yelled, "That's why we use three-year averages, moron." Yes, the intent of three-year averages is to minimize variance, but it falls short of accomplishing that objective. For the formula to truly flesh out all bias, every aspect of the inputs need to be the same, home and away. This includes weather, wind, handedness, team quality… everything.

The best way I can support this is presenting average standard deviations for factors of different sample sizes. It stands to reason the smaller the sample, the larger the variance. So, what we'll look at is

A. Left-handed hitter home run factor
B. Right-handed hitter home run factor
C. Run factor

I took the corresponding individual factors from 2014-2016 and determined each factor's standard deviation for each venue, then averaged the result for all 30 teams. A has the smallest sample while C possesses the largest since run index isn't calculated by handedness. As such, if variance isn't eliminated, A should have the largest average standard deviation with C exhibiting the lowest.

Avg SDHighLow

Sure, enough, that's exactly what we see. The highest and lowest individual standard deviation is included to further validate the claim. I feel comfortable contending the three-year average helps, but does not wholly remove variance.

All that said…

3. It's still better to use park factors than not

The key is to keep in mind that the quality of the opposition is also a huge factor. You don't want to start a pitcher in a pitcher's park if the opposing offense is well above average. On the flip side, you don't want to sit a pitcher scheduled to work in a hitter's park if they'll face an inferior lineup. Park indices are just part of the big picture.

Now the fun part. What ensues is a review of each MLB park. Please note I use what I call composite factors. Something not discussed above is the imbalanced schedule. This is another factor that skews the formula. To combat this, I developed a novel approach, which is essentially a weighted average of the venues in which each team will play. The team's park factor counts 81 times. The other 81 data points correspond to the number of games the team plays in each venue on the road. Those that use park factors in their projections know an adjustment is necessary, as you only want to apply half the factor's impact to the neutral projection. The idea being the road factor is assumed to be 100 for 81 games so the player realizes the home factor only half the time. Using composite factors eliminated the need for that adjustment since the road tilts are factored in along with only 81 home data points.

The traditional adjusted three-year factor is presented along with my composite factor. They're usually close, but in some instances, the difference can be used to gain an advantage with some players.

One final note. If you're using these for DFS, you'll want to use the unadjusted three-year average. That is, the run factor for Chase Field is 115. The 108 shown below is what is used to adjust an individual Diamondbacks' full-season projection. The quick math is for factors over 100, double the amount over and add that to 100. For factors under, double the amount under 100 and subtract that from 100.

National League

Arizona Diamondbacks, Chase Field

3-year 108 104 105 100 99
composite 108 105 106 99 100
St Dev 8.1 20.6 31.5

The perception is Chase Field is a hitter's paradise, and it is. However, it may not be as helpful for power as you think. The composite HR factors are boosted by Coors Field and Dodger Stadium, balancing the effects of Petco Park and especially AT&T Park. Still, when at home (which is the number DFS enthusiasts need to consider) the impact is good but not great.

Pitchers have a tough time since the ball travels well at altitude, but the venue is also big enough that it's difficult for the outfielders to cover all the ground. Many are expecting a rebound from Zack Greinke, along with growth from Robbie Ray and Taijuan Walker. Whatever improvements they make will be tempered by their home digs.

Chase Field is the most unstable venue in the game with respect to righty power. On paper, this could explain why Paul Goldschmidt's homers fell in 2016. However, the index last season was a whopping 141, so his power drop is even more curious.

Atlanta Braves, Turner Field

3-year 99 95 90 105 105
composite 98 97 90 107 106
St Dev 6.9 16.2 31.1

Obviously, with the club opening SunTrust Park this season, factors for Braves players are up in the air. Based on reports, the park should be friendlier for left-handed power, so Freddie Freeman owners should be encouraged.

The main idiosyncrasy with Turner Field was a rather significant boost to both walks and whiffs. It'll be interesting to follow if the same trend holds in the new place. Something to keep in mind is while the formula is supposed to remove bias, it doesn't entirely. Atlanta gave their rotation a serious makeover, bringing in some veterans to replace the dumpster fires they've deployed lately. It wouldn't be shocking to see a BB factor closer to neutral.

Something else to note is SunTrust Park is laid out so the home plate to pitcher's rubber axis points south. MLB politely suggests this to be east-northeast for all parks but apparently, the designers respectfully declined. How this impacts things, especially in day games, remains to be seen. One must believe the architect took this into consideration when drawing up the blueprints. In case you're laughing because they forgot to build bullpens in AT&T Park, that yarn is untrue.

Most thought Turner Field to be a pitcher's park, but it played almost neutral. If the only difference is more lefty homers, SunTrust Park should again land near neutral.

Chicago Cubs, Wrigley Field

3-year 96 108 91 102 103
composite 97 111 96 103 104
St Dev 4.2 23.5 30.8

Holy home run variance Bartman, I mean Batman. Perhaps it's the Windy City living up to its moniker, but the old yard on the North Side plays all over the place with regards to homers. The party line is Wrigley plays pitcher friendly early in the season, as the temperatures are cooler and the wind usually blows in. As the ivy turns green, the warmer weather turns it more hitter friendly. Maybe that's true, a study on first half versus second half park factors will be included in the Z Book.

There's a difference between the composite factor for lefty power and the one that most will use, resulting in a couple of homers. However, that, combined with the LHB HR variance lends considerable upside to Anthony Rizzo and Kyle Schwarber.

Curiously, the R factor has been remarkably stable, not to mention pitcher friendly. Here's a good example of the park factor and the quality of team being different. At least on paper, the Cubs offense would be even more prolific in a more hitter friendly venue. The key to that last thought was "on paper," though. The defending World Series Champions are known for outstanding defense. Strong defense plays better in smaller confines. Plus, Wrigley Field has numerous quirks, not to mention more day games than any other venue. It very well may be that there's some bias resulting from defensive prowess playing better at home lowering the run factor. This could put the visiting bats in play for DFS if the Cubs are using a back-end starter with a weaker defense. Most will use the unadjusted R index, which bakes in the superior defense.

Cincinnati Reds, Great American Ballpark

3-year 101 106 115 104 103
composite 101 107 118 103 107
St Dev 8.5 5.1 21.2

Nicknamed the Great American Smallpark, The GAB has the reputation of being a hitter's haven. While homers do leave the yard at an accelerated rate, especially from the left side, the venue plays just a little beneficial for runs. With smaller dimensions, it's easier to cover the outfield so that which doesn't clear the fence is caught at a higher rate than in larger pastures.

In addition, although free passes are embellished, so are punchouts. The impact of more whiffs is more beneficial than the detriment of higher walks, contributing to the lower than perceived run factor. This bodes well for a couple of young Reds starters, Amir Garrett and Brandon Finnegan. While it's always best to stream, or use pitchers in home affairs for DFS, don't be afraid to use an opposing hurler in Cincinnati. At least don't refrain from doing so because of the venue.

Colorado Rockies, Coors Field

3-year 122 113 108 92 100
composite 120 112 108 91 100
St Dev 6.5 12.5 7.8

Altitude plus vast acreage equals a very tired scoreboard operator. Note Coors Field isn't the top homer hitting venue (Miller Park and Yankee Stadium are better) though it is, by far, tops for runs. Fences were raised, which has cut down a bit on the long balls.

Along with the extra homers from altitude and hits from the huge outfield territory, also affecting scoring is fewer strikeouts. There isn't as much movement on pitches in thin air, increasing balls in play, which is a good thing. That note came courtesy of Lord Obvious.

Los Angeles Dodgers, Dodger Stadium

3-year 94 98 109 102 93
composite 96 99 109 101 94
St Dev 6.1 17.6 15.1

Dodger Stadium, singular, like Cracker Jack, is tied with Safeco Field as the second-best pitcher's park in the game, behind only The Aquarium, also known as Marlins Park. Hey, it's a better nickname than Chavez Ravine.

Despite suppressing runs in a big way, Dodger Stadium is a boon for power, particularly for lefty swingers. This is encouraging for those hoping Adrian Gonzalez rebounds in the homer department as well as for Corey Seager and Joc Pederson. In fact, this makes Pederson an even better play in DFS GPPs.

If you're looking at the reduced BB index and thinking "Clayton Kershaw," think again. Sure, over the past three seasons his home 1.06 BB/9 is lower than his 1.57 road mark, but that's not nearly enough to account for Dodger Stadium's propensity to limit walks.

Miami Marlins, Marlins Park, aka The Aquarium

3-year 92 89 96 103 101
composite 96 91 89 102 105
St Dev 9.2 9.3 13.7

Opened in 2012, Marlins Park underwent significant renovations prior to last season. The fences were brought in and lowered, in an effort to increase homers and scoring. Small sample size alert: The R index fell precipitously last season though homers increased, as hoped.

The runs standard deviation is telling. The larger the raw number, the greater the potential variance. Marlins Park's high variance comes despite a lower R index, reducing the confidence in the three-year average. The two seasons prior to last year, it played 95 and 101. I'll wager this season's R index jumps into the mid-nineties, if not higher. This tempers expectations for Wei-Yin Chen, Adam Conley, Edinson Volquez and most notably Dan Straily. Straily is considered a sleeper by some who perceive him getting a huge boost from park effects. Yes, Marlins Park is a better place to pitch than Great American Ballpark, but the difference isn't as extreme as some may intuit.

Milwaukee Brewers, Miller Park

3-year 101 106 125 102 100
composite 102 107 124 101 99
St Dev 6.8 15.1 8.1

Miller Park is a lot like Great American Ballpark in that homers are plentiful but the smaller dimensions neutralize runs. This makes Zach Davies especially attractive, but also aids Wily Peralta, if he can maintain last season's second half gains, as well as Jimmy Nelson (I'm not giving up yet).

There isn't a split better for homers in MLB than Miller Park for left-handers. Keep that in mind when the room laughs at you for grabbing Eric Thames. The joke could be on them.

Miller Park is one of the more stable venues as evidenced by the moderate standard deviations. Perhaps this is a result of the retractable roof. With it closed, the yard is subject to less impact from weather.

New York Mets, Citi Field

3-year 100 110 102 106 110
composite 95 101 102 102 106
St Dev 7.6 23.5 13.7

Citi Field could be the toughest to gauge. It's undergone several different renovations, most recently leading into the 2015 season with the fences in center and right brought in and lowered. Most omit the 2014 season from the average. I'm not comfortable doing that. Truth be told, all the numbers are so wacky nothing is really trustworthy.

That said, I need to have something to factor into the projections so I see Citi Field as a pitcher's park that increases homers a tick. But check out the standard deviations. The venue has played both ways lately.

Adding to the confusion is last season, when right-handed power skyrocketed. Most of the renovations have been to right field, which shouldn't impact right-handed hitters as much. In 2014, the LHB HR index was 105. It dropped to 82 in 2015 before ballooning to 129 last year. The reason I'm comfortable considering Citi Field a pitcher's park is I doubt the 129 will repeat. No significant changes were made to the pull side for righties. Fewer homers should mean fewer runs, and a lower R index.

I'm not sure what to think about the fact Citi Field has increased walks almost 20 percent compared to a neutral yard. There isn't really anything special about the dimensions or surroundings to enact that discrepancy. Still, it's something to consider when streaming opposing pitchers.

Philadelphia Phillies, Citizens Bank Park

3-year 97 112 104 104 100
composite 96 112 101 105 103
St Dev 10 24.1 18.9

Not only is CBP not the hitter's park it's perceived to be, it's favorable for pitchers in terms of runs allowed. It embellishes power, but there are two latent factors depressing scoring. The first is Citizens Bank Park has aided strikeouts. The other is that only the former O.Co Coliseum in Oakland generates more foul outs than CBP. There's nothing that screams "more foul outs will happen here," but it's been the case for several seasons. As such, arms like Aaron Nola, Jerad Eickhoff and Vince Velasquez are even more appealing. This also explains the rejuvenation of Jeremy Hellickson.

Citizens Bank Park ranks only behind Coors Field and Yankee Stadium in terms of right-handed pop. Unfortunately, other than Maikel Franco, the Phillies aren't built to take advantage, which may help explain the low R index as opponents may be benefiting more than the home team.

Pittsburgh Pirates, PNC Park

3-year 99 88 101 96 101
composite 99 92 105 98 103
St Dev 4 26.1 13.1

While PNC is favorable to pitchers, it may not be to the extent many believe. The main reason is the venue isn't a death knell for lefty power as it is for righties. In addition, it's towards the bottom when it comes to foul outs, along with slightly suppressing punchouts. A pitcher earns his outs in PNC Park.

Most noteworthy is because the Bucs play in the same division as the Reds and Brewers, they visit two of the more favorable home run parks frequently. This, along with interleague tilts in Camden Yards and Rogers Centre, yield a higher composite HR index from both sides of the dish. Perhaps this helps Andrew McCutchen rebound, as well as adding a couple dingers to Starling Marte's ledger.

San Diego Padres, PETCO Park

3-year 101 103 87 98 97
composite 98 99 96 100 100
St Dev 9 18.4 18.1

Opening in 2004, PETCO Park was a pitcher's paradise until it was renovated prior to the 2013 campaign. The modifications entailed bringing in the fences all around while shortening the wall in right. It helped, as the venue has played closer to neutral in recent seasons, though it's still tough on power, especially from the left side.

Some minor changes were made for the 2015 season so many are not including 2014 in the park average. I am, as I don't feel the alterations were enough to take the third season out of the average, so I treat PETCO Park as slightly pitcher-friendly. That said, there are those that still consider it an extreme pitcher's park. This could present a buying opportunity on youngsters Manuel Margot and Hunter Renfroe, as some may assume the venue will hurt their numbers. Power, yes, but their production won't be knocked down as much as some assume.

San Francisco Giants, AT&T Park

3-year 96 87 80 101 102
composite 98 89 83 99 100
St Dev 8 3.5 9.3

There's not much to say about AT&T. It's squashes power more than any venue from both batter's boxes, though it is curious that the park played a tick hitter friendly last season in terms of runs. There weren't any changes so that's likely just noise. I'd expect AT&T to again be one of the leaders for decreasing runs.

St. Louis Cardinals, Busch Stadium

3-year 99 93 99 96 99
composite 99 95 102 96 99
St Dev 10.1 5.6 11.1

Busch Stadium's R index is a little misleading, Last season it played 92, checking in at 93 in 2015. In 2014, the factor was 110, hence the average being close to neutral with a big standard deviation. My gut says it returns to playing more favorably towards pitchers.

If you're looking for an edge with a Cardinal, left-handed power plays better in Busch Stadium than many realize. Embellishing this is road dates in Cincinnati and Milwaukee. Matt Carpenter and his new-found power stroke stand to benefit most, and perhaps Kolten Wong will get a boost too if he plays regularly.

Washington Nationals, Nationals Park

3-year 101 100 92 100 101
composite 100 100 91 100 104
St Dev 5.6 25.7 11.3

Here's an intriguing quirk. Right-handed power may not be neutral, as the 3-year average is dragged down by a 69 RHB HR index in 2014. In 2015 it was 114, playing 113 last season. Any mark above 69 this season will bring next year's factor over 100. If it plays similarly to last season, we're looking at one of the top-five venues in the National League with respect to right-handed homers. Great, just what we need, another reason to validate Trea Turner as a first rounder.

Other than the possibility Nationals Park gives a latent advantage to righties, there isn't much to say. The general perception is it plays neutral, and it does.

American League

Baltimore Orioles, Camden Yards

3-year 102 103 108 97 99
composite 103 106 110 97 98
St Dev 16.8 26 21.7

OK, check this out. Here are the R index three-year averages for Camden Yards, starting in 2010: 106, 104, 109, 107, 105, 107 and 103. Pretty consistent, right? Now the individual R factor for those years: 111, 99, 117, 106, 93, 123 and 95. I know, that's why we utilize the three-year average. But man, only in one of those years did the park play like it was supposed to. Yeah, I could do this exercise with just about every park, but Camden Yards has the biggest R factor standard deviation. I guess we have to consider it slightly positive for runs, but there's a chance it could play better for pitchers or even be one of the best in league for scoring.

Where this comes into play is with Kevin Gausman and Dylan Bundy, a couple of promising righties on the verge of taking the next step. I'd like to be confident saying the park will help or hinder, but I don't know what it will do.

Mark Trumbo and Chris Davis owners take heed. Not only does Camden Yards aid their handedness, the composite factor buoys it even more.

Boston Red Sox, Fenway Park

3-year 108 103 88 97 101
composite 108 105 92 97 102
St Dev 7.2 17.1 13.3

There was a time most still thought of Fenway Park as a home run haven, perhaps because the squad usually has sluggers, masking the fact it's hard to hit one out to right since the Green Monster hasn't played as close after the 600 Club was constructed over the stands behind home plate. Granted, it still is positive for righty power, but it isn't the homers that should worry David Price, Chris Sale, Eduardo Rodriguez, Drew Pomeranz and their owners. It's the balls that ping off The Wall that would have been caught anywhere else.

Fenway Park may depress homers, but the Monster boosts doubles while the triangle in center and the quirky dimensions in right elevate triples. All that renders Coors Field as the only venue better for runs, though the Friendly Fens is a distant second. The Green Monster turns outs into hits, adding runners and extending innings. Add in one of the smallest foul territories and it's no wonder the Fenway Park hit factor is also only bettered by Coors Field. The foul territory, in addition to an excellent batter's eye, knock strikeouts down in Fenway, something else to keep in mind when evaluating Chris Sale and David Price, if and when he returns.

Chicago White Sox, Guaranteed Rate Park

3-year 98 104 107 104 103
composite 99 104 107 104 102
St Dev 7.9 5.1 15.9

Figures, it takes fantasy baseball for me to finally learn to spell "guarantee" properly. The venue formally known as US Cellular Field is another that is miscast as a hitter's park. Yes, it's good for power, but the quaint confines reduce hits, and hence runs. In addition, it embellishes strikeouts, another reason to temper expectations with Sale, as Fenway Park reduces whiffs.

Something to consider is the Pale Hose have the heaviest concentration of southpaw arms in the league. This is one of those elements that falls under the "built for the park" mantra. I don't know for sure, since they also led the league in left-handed pitches in 2014, but the three-year trend for run factor is 105 in 2014, then 90 and 93 last season. Especially if Jose Quintana is traded, it will be interesting to see if the R index changes with the loss of two solid lefties.

Cleveland Indians, Progressive Field

3-year 107 103 105 99 103
composite 108 103 106 98 102
St Dev 16.6 1.5 21.5

You could win some bar bets asking what venue is second in the American League for R index. Progressive Field boosts runs a lot, while only moderately helping power. Lower strikeouts and high walks helps, as does the second fewest foul outs in the league next to, surprisingly, Coors Field.

You know what? Something doesn't feel right. Here are the R factors since 2010: 95, 96, 90, 93, 95, 126, 121. Two of these things aren't like the others.

While there haven't been any renovations to the playing field, some changes were made to right field with respect to the stands and amenities. Sometimes, this changes the wind pattern. The problem with that is the LHB HR indices don't reflect an improvement necessary to support such a big increase in runs. Since 2010, the factors are 116, 146, 102, 117, 110, 90, 133. The factor from 2015 is out of sync, but that's not unusual given the small sample of lefty hitters.

There must be something else influencing the huge bump in park factor. Any idea what it could be? I don't know for sure, but here's a hint to what I think may be the answer: Francisco Lindor, Jose Ramirez, Carlos Santana and to a lesser extent, Coco Crisp and Abraham Almonte.

Figure it out? They're all switch-hitters. Plus, Cleveland employed a platoon in right field. The Tribe had the most plate appearances with the platoon advantage in MLB last season, placing second in 2015. The counter is they also led the league in platoon-edge late appearances in 2014, finishing second in 2013, so the argument is losing traction. I suppose I could anecdotally suggest the difference is Francisco Lindor and Jose Ramirez the past two seasons, but that doesn't seem like it will hold up in court.

Still, there's something bizarre going on. You're not likely to stream opposing hurlers against the Indians regardless, though this season's lineup is sketchy. For me, I'm not going to downgrade Cleveland's own starters because of the venue, like I might for Sale and Price in Boston.

Detroit Tigers, Comerica Park

3-year 99 100 100 97 100
composite 100 102 101 99 100
St Dev 6.4 21.1 39.8

By the numbers, Comerica Park plays as close to neutral across the board as any in the game. The surprise there is that many perceive it to be more of a pitcher's delight. It leans that way, but there's ample variance to just call it neutral.

Speaking of variance, the HR index from both sides of the plate is big. Last season, the venue was the most favorable in the game, registering a whopping 147 for LHB HR. The preceding campaigns it was a power crushing 77 and 79. The Tigers don't have any lefty swingers joining their team, but if they did, I'd be leery of applying the three-year average, as it's more likely the venue still hinders left-handed pop.

Houston Astros, Minute Maid Park

3-year 96 100 102 105 98
composite 96 100 104 106 98
St Dev 10.1 12.7 29.7

Yet another venue perceived to be a hitter's park, Minute Maid has suppressed runs lately. In addition, homers aren't as easy to come by as some believe.

Curiously, the removal of silly Tal's Hill in center field concurrent with bringing the fences in from a max of 436 feet to 409 feet hasn't received much attention. Changes to straightaway center may not be as momentous to either pull side, but ample balls are hit up the middle for it to make a difference. Looking at spray charts, I count ten to 15 extra homers a season. Of course, some of those were extra-base hits anyway. I haven't taken this step yet, but with the available data, it's possible to determine how many outs should be gained/lost. It stands to reason the park will now play more hitter-friendly.

DFS players know the Houston lineup is a great source of strikeouts, in part because Minute Maid boosts punchouts. Another repercussion of removing Tal's Hill could be a better batter's eye. We'll see. Get it, SEE? Sigh, if you have to explain a joke…

Kansas City Royals, Kauffman Stadium

3-year 104 91 90 97 98
composite 105 92 93 98 97
St Dev 9 7.6 13.6

Perhaps the most misunderstood venue, Kauffman Stadium plays as a hitter's park despite crushing power to all fields. Depending on the scoring of the DFS site you're playing, stacking at The K can be fruitful, especially if the lineup has some hitters with the power to overcome the HR index.

It's hard to discern cause from effect, especially since I've noted ad nauseum how unreliable even the three-year average can be, but another note stemming from DFS: using a pitcher against the Royals in their home digs limits his strikeout upside. On the other hand, it depresses walks as well. Again, chicken or egg, as the Royals are a team known to put the ball in play. Are the factors organic to the park or is the team designed in such a manner that the whiffs and walks are both down, and the venue does not flesh out the bias? My lean is the park plays a significant role, hence while I like Danny Duffy, although he may fan a few less than some anticipate.

Los Angeles Angels, Angels Stadium

3-year 95 99 94 104 98
composite 95 99 95 105 97
St Dev 3.2 9.5 15.8

No surprises here, the big ball yard in Anaheim is one of the best in the game for pitchers. It's favorable across the board. Of course, some of this feeds into the others, but strikeouts are amplified and walks are tempered, embellishing the fact homers are lessened. The result is one of the consistently best parks for hurlers in terms of runs allowed.

Health will be key, (no duh, Lord Obvious) but if Garrett Richards and Matt Shoemaker can avoid injuries, they join Tyler Skaggs as great investments. Plus, don't laugh, Ricky Nolasco, Jesse Chavez and Bud Norris become relevant in extremely deep formats.

Minnesota Twins, Target Field

3-year 103 103 95 95 97
composite 105 104 99 95 97
St Dev 6.6 7.9 14.4

Well, we're back to another venue often misjudged. Target Field looks big, and it does hold back lefty power, but overall it aids righty power and especially runs. There's no obvious explanation, but low walk and whiff factors suggest the batting eye could be very good.

From a fantasy perspective, if you're looking for a couple of under-the-radar hitters, Max Kepler and Eddie Rosario both swing left-handed and thus should benefit from the composite LHB HR factor, as that could add a couple more homers to their respective totals compared to the market's expectation.

New York Yankees, Yankee Stadium

3-year 100 113 123 102 100
composite 101 114 125 102 101
St Dev 5.3 20.5 14.5

In what may be one of the bigger surprises, Yankee Stadium plays around neutral for runs. Even the composite factor from playing in the AL East isn't daunting. The actual R indices the past three seasons have been 92, 102, and 104 last year. One could suggest it's trending upward, but even 104 isn't that alarming.

Everyone knows about the short porch in right, and it's no surprise that Yankee Stadium is second to only Miller Park for LHB HR. In what may be a case of "built for the park," righty swingers with oppo power can also take advantage. Everyone thinks pull field when they see a HR index, but it's not the factor for the field, but for the handedness of the batter. If the Yankees have an above average number of righties with power the other way, it would be reflected in the RHB HR.

My main takeaway is not to shy away from using pitchers in the Bronx, especially if they're groundball guys. Further, the Yankees lineup may not be as damaging as in past seasons. This also pushes Masahiro Tanaka up my ranks, even though his primary bugaboo is the long ball.

Oakland Athletics, Oakland-Alameda County Coliseum

3-year 97 91 90 97 98
composite 96 91 91 99 98
St Dev 9.5 7.4 12.8

Previously, Angels Stadium was deemed one of the best pitching parks in the game. The Coliseum rivals it, though lagging a bit in strikeouts. The aspect that lifts the Coliseum into the extreme pitcher's park stratosphere is the vast amount of foul ground. More foul outs occur in Oakland than any other venue.

In a weird way, the added foul outs hurt pitchers for fantasy as that decreases strikeouts. This isn't nearly enough to avoid Sean Manaea, Jharel Cotton and Andrew Triggs, but it does hinder pitchers for DFS where strikeouts are paramount.

Seattle Mariners, Safeco Field

3-year 94 101 105 104 98
composite 94 101 105 104 99
St Dev 6 13.7 12.7

May I have the envelope please. The winner of best pitcher's park in the American League is… Fenway Park.

Hmm, I think I was handed the wrong envelope. Safeco Field is the real winner.

There have been modifications to the venue to increase homers, but run scoring hasn't piggybacked. If you're a groundball specialist in Safeco Park, your chances of success are even greater. The park increases homers while reducing whiffs, perhaps lending King Felix a hand as he tries to reinvent himself again.

Please sit down for this last note. The characteristics of the venue mesh perfectly with Yovani Gallardo. He's a groundball pitcher who needs some help with adding whiffs and losing walks.

Tampa Bay Rays, Tropicana Field

3-year 97 92 100 104 98
composite 98 96 106 104 101
St Dev 5.5 5.5 44

Considering the Rays are housed in the same division as Camden Yards, Yankee Stadium and Rogers Centre, it makes sense their composite HR factors give them a nice little boost. This could break a tie if you're considering Evan Longoria, Brad Miller or even Kevin Kiermaier in the mid-rounds of a draft.

More interesting is the notion that Tampa pitchers are at a disadvantage having to play in the AL East. Yeah, maybe, relative to other divisions, but is it enough to discount them significantly? No, not at all, especially with lefties as the RHB composite HR factor is below average. Unfortunately, Blake Snell is the only southpaw in the pipeline, though it isn't a bad idea to push him up the ranks a tad.

Texas Rangers, Globe Life Park

3-year 106 100 103 97 102
composite 104 100 103 100 101
St Dev 5.9 13.5 7.6

I bet a few of you are thinking, "I didn't know that was its name." The Ballpark in Arlington was formally renamed Globe Life Park in 2014. The venue has undergone some renovations, cutting down on the wind tunnel out to right field and dropping the HR indices considerably. However, the park still rates as one of the five best for runs in MLB.

To be honest, I'm more reticent to stream pitchers in Arlington than any park except Coors Field and Fenway Park. Most of the high-scoring yards also have high home run tendencies. The scary thing about Globe Life is it embellishes runs without homers, so if a hurler also has gopheritis, he's in double trouble.

Toronto Blue Jays, Rogers Centre

3-year 102 105 105 101 100
composite 103 108 108 103 98
St Dev 12.5 22 17.9

This deserved mentioned earlier, but DFS players should be aware of all parks with retractable roofs, as those venues tend to play differently with it opened or closed. It's too bad there aren't any more domed stadiums to really demonstrate the variance with park factors, but I digress.

Speaking of DFS, stacking in Rogers Centre is one of my favorite ploys, not just because it's a hitter's park but also due to homers coming with the runs. Not to mention, you know the game will be played, as opposed to all the slates where rain puts a Coors game in jeopardy.

Lastly, in season-long leagues, I have a stigma about Blue Jays starters since the park is so punishing in terms of both runs and homers. Perhaps it's unwarranted, but other than Roberto Osuna, I'll be sparsely invested in Blue Jays arms.


Yes friends, we're nearing the end. Hopefully it's apparent why park factors drive me batty. We're absolutely better off using them than not, but they're not as precise as a numbers nerd would prefer. Yes, I apply the static number when doing projections, but just like other elements of the projection, there's noise, rendering the projection a range and not a fixed set of numbers.

My favorite means of employing factors in-season, and to a degree in drafts, is recognizing the quirky venues as those often result in the misidentification of a player's potential, for better or worse.

Here's a series of groupings by park characteristics. The names are in no particular order, with those sometimes misconstrued denoted with an asterisk.

High R, High HR

Camden Yards (Orioles)
*Progressive Field (Indians) – perceived lower for runs
Chase Field (Diamondbacks)
Rogers Centre (Blue Jays)
Coors Field (Rockies)
Globe Life Park (Rangers)

High HR, Just over Neutral R

*Great American Ballpark (Reds) – thought to be better for runs
*Yankee Stadium (Yankees) – thought to be better for runs
*Miller Park (Brewers) – thought to be better for runs

Neutral HR, Neutral R

*Comerica Park (Tigers) – assumed pitcher's park
*Wrigley Field (Cubs) – though to be more of a hitter's park
*PNC Park (Pirates) – assumed pitcher's paradise
*Busch Stadium (Cardinals) – assumed pitcher friendly

Just Over Neutral HR, Just Below Neutral R

*Tropicana Field (Rays) – more homers than expected
*Minute Maid Park (Astros) – assumed hitter's haven
*Citizens Bank Park (Phillies) – thought to be better for runs
*US Cellular Field* (White Sox) – thought to be better for runs
Citi Field (Mets)
Dodgers Stadium (Dodgers)
*Safeco Field (Mariners) – higher HR mark then expected

Low HR, Low R

PETCO Park (Padres)
Angels Stadium (Angels)
Marlins Park (Marlins)
Oakland-Alameda County Coliseum (Athletics)
AT&T Park (Giants)

Low HR, high R

*Kauffman Stadium (Royals) - thought to be pitcher's park
*Fenway Park (Red Sox) – perceived to be more homer-friendly

We'll conclude with this word of warning. Given park factors are intrinsically noisy, each player is not going to be influenced perfectly in line with it. This is particularly relevant for players joining a new team. Be careful assuming a new home will affect the player to the full extent of the factor, in either direction.

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Todd Zola
Todd has been writing about fantasy baseball since 1997. He won NL Tout Wars and Mixed LABR in 2016 as well as a multi-time league winner in the National Fantasy Baseball Championship. Todd is now setting his sights even higher: The Rotowire Staff League. Lord Zola, as he's known in the industry, won the 2013 FSWA Fantasy Baseball Article of the Year award and was named the 2017 FSWA Fantasy Baseball Writer of the Year. Todd is a five-time FSWA awards finalist.
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