DFS Baseball 101: How to Use Batter vs. Pitcher (BvP) Stats

DFS Baseball 101: How to Use Batter vs. Pitcher (BvP) Stats

This article is part of our DFS Baseball 101 series.

Devising and implementing a successful daily fantasy baseball strategy is truly a multi-pronged approach. With as stat-centric a sport as baseball, the sheer volume of data can be overwhelming, especially for a new player. At the same time, the plethora of numbers at our disposal when preparing a daily fantasy baseball lineup can tempt us into considering any one of them in a vacuum, if only to simplify and cut down our research time. However, with the symbiotic relationship that many baseball metrics share, this approach can often lead us down the wrong path when creating a daily fantasy baseball lineup.

BvP - Looking Beyond The Numbers

In this installment, we'll discuss a particular baseball metric that's become somewhat of a lightning rod of controversy. Within the parlance of daily fantasy baseball contests, the letters "BvP" are capable of provoking more debate and discussion than perhaps any other. The acronym stands for "Batter versus Pitcher," and it is a measure that provides a historical overview of the degree of success (or lack thereof) that a hitter has enjoyed over the course of his career against the pitcher they're slated to face on that day.

On the surface, BvP would appear to be one of the most straightforward and reliably predictive factors in daily fantasy baseball research. However, this sport can be finicky at times, one that doesn't necessarily conform to what our expectations might be given a particular matchup. Therefore, it behooves us as daily fantasy baseball players to invest time in looking beneath the surface of any one metric, particularly BvP, to ascertain the predictive quality of that number as much as possible.

(Sample) Size Matters!
When reviewing an initial BvP line on any player, one factor we can immediately evaluate is sample size. Generally speaking, it's virtually impossible to gage the veracity of a poor or outstanding BvP history if it consists of seven at-bats. We want to make sure that we're looking at a minimum of 15-to-18 at-bats (approximately 5-to-6 games worth) to give any one BvP history credence, as a sample size of at least that amount helps to largely filter out random bounces of the ball, a couple of misplaced pitches and other quirks of that nature. Ideally, we'd love to see at least a 20-to-25 at-bat sampling every time, but that isn't possible nearly as often as we'd like. Additionally, larger sample sizes for BvP in daily fantasy baseball can be a bit of a Catch-22, as they can unearth an often overlooked factor: stale data.

The Perils of Stale Data
This is where BvP analysis in daily fantasy baseball can become part archaeological dig. Say we get lucky and find that a hitter we've got under serious consideration for that evening's slate happens to have a nice, robust history against the opposing pitcher. We're talking a plump, 40 at-bat sampling that you can really sink your teeth into. The other side of that coin is that now we've got to make sure the successes we see reflected in that stat aren't ancient history.

For example, are we inadvertently overlooking that 90 percent of the extra-base hits and homers the hitter tallied against the pitcher are clumped together over a two-season period from the last decade? We certainly could be, especially with veteran players, if we're not taking the time to break down that BvP data by reviewing how those numbers have been spread out over time. In other words, we'll need to take a look at a season-by-season breakdown to see how things have transpired between hitter and pitcher for the last 2-to-3 years. By doing so, we're greatly enhancing the potential predictive ability of that data for that night's game, which is ultimately all we're concerned about.

Keeping BvP "Honest" - The Importance of Weighted On-Base Average

One of the better metrics to utilize in conjunction with BvP to guard against possible misinterpretations is Weighted On-Base Average (wOBA). We'll discuss the concept more in depth in a future installment, but simply put, wOBA attempts to properly rank the importance of each of the ways a hitter can get on base by providing each event with a different weight.

For example, doubles, triples and home runs each have greater value than a single or walk in an actual game, yet they are all treated equally when calculating standard batting average. This inefficiency is eliminated when calculating w0OA, as extra-base hits and home runs factor into the overall figure at a greater rate than a bloop single to center field.

How exactly does wOBA help keep BvP honest? By providing a glimpse of a larger body of work for that hitter against pitchers of the same handedness as the one they're facing that night. Say Hitter X has an appealing history against that night's opposing pitcher, a southpaw, over a decent sample size of 16 at-bats. However, you're not quite convinced based solely on that (as you rightfully shouldn't be), and want to see if your guy regularly tees off against lefties overall.

After all, his history against left-handers, assuming he's been in the league at least a couple of seasons, is inevitably going to be much more extensive than the BvP sample. Furthermore, when reviewing wOBA against an overall handedness of pitcher, you can customize the sample size to whatever span of time you'd like. If you want to focus primarily on last season, which might be the case early in a new year, you can go that route. However, if you want to take a longer view, you can look two, three or four seasons back as well if the data is there.

Additional Factors To Consider

In addition to drilling down on BvP by examining it on a season-to-season basis, and bringing wOBA in as a confirmative metric, what other nuances should we be mindful of to ensure we're not coming up short in our research? There's actually a few more factors that I consider important parts of the overall picture when evaluating BvP data:

Home/Road Splits for BvP Data
Many casual daily fantasy baseball players may not take this extra step, but there are certainly instances when BvP success is not only concentrated over a particular period of time, but in a particular ballpark as well. In other words, be mindful of a player who's obliterated a certain pitcher in the hitter's offense-friendly home park, but is typically stymied when facing the pitcher on the road.

Lineup Factors
Despite its reputation as a sport heavily predicated on individual achievements, there are countless team elements in baseball that affect those individual performances. Knowing where the hitter you're evaluating is slotted in the lineup tonight, as opposed to where he may have been in previous instances, can be a fairly important piece of information. If the player you're considering is a former leadoff hitter who's been demoted down to the eight-hole, he's likely to have diminished RBI opportunities and probably won't see the same quality of pitches as when he was much higher in the order.

That dovetails into another factor that goes hand-in-hand with your hitter's place in the lineup: which players are around your hitter in his current spot in the batting order? If, in previous encounters with the pitcher, he was protected by a couple of mashers behind him, he certainly may have seen a certain quality of pitch that greatly increased his chance for success. However, if he's been the subject of the aforementioned demotion to the eighth spot, and consequently now has the .200-hitting shortstop as his "protection," chances are he won't see too many balls near the strike zone.

Batting Average of Balls In Play (BABIP)
This is another concept that we'll elaborate on in future discussions of daily fantasy baseball strategy, but it merits a quick mention in relation to evaluating BvP. Simply put, BABIP can sometimes be a good explanatory tool for extreme success, particularly over a more condensed period of time. It essentially measures what its name implies: the rate at which a hitter has been able to hit safely each time he's made contact. Unlike wOBA, BABIP is a catch-all metric. It's going to treat that lucky bloop single stemming from a pitch where the hitter got handcuffed the same as the offering he put the screws to and blasted off the wall in deep center for a triple.

Let's apply it to a BvP hypothetical for a moment: Hitter X might have a solid 10-for-18 history against a particular pitcher, catching your eye immediately when starting your daily fantasy baseball research for that particular day. However, you also note that there's a corresponding .500-plus BABIP attached to that BvP history, which not only is an obviously unsustainable number over an extended period, but could also well be an indicator of Lady Luck having made her presence felt on a few of those at-bats. At that point, you might be well inclined to perform your due diligence on the other aspects of we've already discussed, to either confirm or perhaps disprove that gaudy BvP number.

As you can see, BvP is just one of many tools that can be used when making decisions for your daily fantasy baseball lineup. There's an abundance of debate about its predictive value, but you can insulate yourself from the hazards of over-reliance on it by simply treating these other accompanying factors as equally important parts of your research.

The author(s) of this article may play in daily fantasy contests including – but not limited to – games that they have provided recommendations or advice on in this article. In the course of playing in these games using their personal accounts, it's possible that they will use players in their lineups or other strategies that differ from the recommendations they have provided above. The recommendations in this article do not necessarily reflect the views of RotoWire. Juan Carlos Blanco plays in daily fantasy contests using the following accounts: DraftKings: jcblanco22, FanDuel: jc_blanco22, DraftPot: jc_blanco22, FantasyDraft: jc_blanco22, OwnThePlay: jcblanco22.
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Juan Carlos Blanco
Winner of the FSWA 2016 Newcomer of the Year Award, Juan Carlos Blanco has been playing fantasy sports for over 20 years and covers NBA, MLB, NFL, CFL and Arena Football for Rotowire.com, including serving as the beat writer for teams in multiple sports. He has previously written for KFFL.com and remains an avid season-long and daily fantasy player in multiple sports as well.
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