The Z Files: Under the Microscope -- Fernando Tatis

There's been chatter Fernando Tatis could be the top overall pick in 2021 drafts. To be honest, a couple weeks ago he was all but handed the distinction, but a 2-for-27 stretch has pumped the brakes, at least a little. Through Wednesday night's action, Tatis was still the top earner among batters, despite the recent struggles.

The slump has also quelled some of the internet trolling directed at those of us having the nerve suggest Tatis was in store for some regression. The fact is, the Padres superstar has regressed in the BABIP department, as expected. Countering that is a leap in power along with improved plate skills.

Currently, Tatis is sporting a .310 BABIP, exactly 100 points below last season's bloated mark. Much to the consternation of the trolls, the regression monster strikes again. Let's look at some component batted ball data to see what's happening.

Before presenting the numbers, please keep in mind even today, batted ball data differs by source, so some of the stats presented here may not match up with what you find elsewhere. The key is consistency and using the same source throughout the study, which is what was done here. League average data is included to provide perspective.

KEY

• AEV: Average Exit Velocity
• LA: Launch Angle
• BABIP: Batting Average on Balls In Play (H – HR)/(AB – K – HR + SF)
• Dist: Average Distance

Ground Balls

Tatis

League Average

It will become quite apparent very soon, Tatis hits everything hard. As such, he's likely to carry a BABIP much higher than league average.

Something to note with the 2020 groundball data is his BABIP is considerably lower than last season, despite hitting the ball harder. There are two elements to this comparison. Tatis' 2019 data was similar to league average, yet his BABIP was nearly 100 points higher. This is some of the luck expected to regress. Sure enough, his BABIP is much lower, but the AEV is significantly higher. In fact,he's been a bit unlucky this season as his groundball BABIP deserves to be a bit higher.

Outfield Line Drives

Tatis

League Average

Holy cow is he crushing the ball this season. His 104 mph AEV on outfield line drives is second to Miguel Sano, well known destroyer of baseballs. The added distance and increased launch angle helps explain Tatis' power uptick.

Fly Balls

Tatis

League Average

Continuing the trend, Tatis has mashed fly balls with elevated velocity compared to the league average. This season's AEV on fly balls is just a little higher than last year's, but when compared to league average, his 2020 mark is about six mph above the normal, almost twice last season's 3.5 mph level.

It's interesting to note his average fly ball distance is shorter this season. The result should be fewer homers, which we know isn't the case. The reason could be his home run total is artificially high and is due some… wait for it… regression.

There's another explanation as well. Home run data wasn't presented with the component hits since there's a fine line between what is considered a fly ball and outfield line drive. Be it subjective or numbers driven, it's an area where there's very little to distinguish one from the other. As such, focusing on the number of homers for each could be a distraction; if a couple borderline fly ball homers were classified as outfield line drives, the percentages would change. The better approach is combining fly balls and outfield line drives when analyzing home runs.

Home Runs per Fly Balls plus Outfield Line Drives

This metric is one likely different from HR/FB found elsewhere. But again, using the same source for both seasons renders the comparison useful. Tatis' mark is a tick higher than last season, but there's still ample games to be played before making a conclusion. One thing is clear, he is capable of a level well above league average.

Prorated to 650 plate appearances, Tatis is on pace for 44 homers, compared to 38 last season. Neither those warning of BABIP regression nor those mocking them for it suggested he would increase his power. That said, if he continues slumping, the prorated total could drop. It's best to see what happens the final nine games before opining, but chances are his power will have improved this season. With the rate displayed in the last table less than a point higher this season, the power spike is the result of lofting more balls to the outfield, a metric which may not be sustainable over a regular six-month season. Or who knows, maybe it increases.

Circling back to the flyball BABIP data, look at the marked difference between the two campaigns. In 2019, there's no way around it -- the young shortstop was lucky in this area, buoying the .410 BABIP.

That said, part of this season's BABIP decline is due to his increased power, since less of his hard contact has stayed IP (in play). Some consider this a bug; it's more an inconvenience so long as you understand what BABIP is, its influences and how to apply it.

Home runs don't factor into BABIP. If a certain fly clears the fence, it doesn't affect BABIP. If the same fly were hit in another park, or on a day with the wind blowing in, perhaps it hits the fence for a double, elevating BABIP. If the wind were gusting in, the same fly would have been caught, lowering BABIP. The point is some of the dip in Tatis' flyball BABIP is from more power, not just regression.

Plate skills

The other area of improvement is Tatis' 2020 plate skills. To wit:

This season, he is putting the ball in play four percent more often. That's 26 more balls in play over 650 plate appearances. If 40 percent of those are lofted to the outfield and 22.4 percent clear the fence, that's two of the six added prorated homers he has slugged this year.

In Summary

There are still nine games left on San Diego's schedule, so it's premature to draw anything concrete. That may not seem like much, but nine games is 15 percent of this year's schedule. The Padres have played the equivalent to 138 games in a normal season so far, and most would want to see what occurs in the final 24 before finalizing analysis.

Truth be told, 60 games is too small a sample to really trust, but that's a story for another day. Even so, I'm comfortable stating Tatis' BABIP regressed as expected, likely too much. Chances are, if there were another 102 games (along with the aforementioned nine), his BABIP would have ticked back up.

The focus of the offseason research on Tatis will be whether his 2020 power output will regress. Even with the full 60 games worth of data, the determination will come with a wide error bar.

If the season were to end today, perish the thought, I'd probably incur the wrath of Tatis fans by conjecturing his power will dip. The reasoning would be that there's risk in expecting his AEV on fly balls, the increase in balls lofted to the outfield and his strikeout rate to all maintain their 2020 levels, as at least one and maybe all three should move towards his 2019 marks.

Whether this takes Tatis out of first overall pick consideration is unclear. In his favor is the 21-year-old phenom can be expected to swipe 20-30 bases in a full season and his run production should be excellent, especially if the National League retains the designated hitter.

Mookie Betts, Ronald Acuna and of course Mike Trout will provide the primary competition. In Betts' favor is a track record of performance at this level, and he hasn't missed a beat with the Dodgers. Trout will benefit from only missing time while on paternity leave. It was just 60 games, but managing, at least thus far this season, to avoid the IL should increase Trout's playing time expectation. Where Acuna is drafted will revolve around how much he's penalized by an increase in strikeout rate, which currently sits at 29.7 percent, and his own big drop in BABIP.

I'll have a sneak peek at how the market ranks these players as we're pulling together the 2021 Premature Edraftulation League, an NFBC satellite in which I co-manage a team with Derek VanRiper -- formerly with RotoWire and now crushing it with The Athletic. The draft should commence soon, perhaps over the weekend.