Mike Trout, Yasmani Grandal, and Other Early BABIP Outliers

When it comes to early-season dominance or struggles, BABIP tends to be a featured player in many of the odder-looking lines. At the top of the league, you have the already amazing Mike Trout sporting a .519 BABIP, fueling a video game-like 236 wRC+ and a 1.224 OPS. On the flip side, quality players are still looking way up at the Mendoza line, such as Yasmani Grandal (.121 BA, .125 BABIP) or Kyle Tucker (.179 BA, .173 BABIP). Even though the evidence suggests that there’s more variability in BABIP ability among hitters than pitchers, a month of a season is a pitifully small amount of time to establish a new baseline expectation for BABIP. So, who is “earning” their BABIP and who isn’t so far?

Similar to the “x” Statcast stats, the ZiPS calculates “z” stats — I’ll let you guess what the z stands for — as part of its year-end projection model. These aren’t yet used in the simpler in-season model, though that’s in the works. Similar to Statcast, ZiPS estimates BABIP from the component parts: launch angle, exit velocity, speed data (for grounders), and so on. ZiPS also considers the direction a ball is hit, as a player’s pull tendency is a repeatable skill. This last data matters quite a bit. For example, grounders hit up the middle end up as singles about half the time, but grounders hit 15 degrees to the left or right of the second base bag are hits about a tenth of the time.

How does it work? The numbers are still volatile, but if all you have is zBABIP and actual BABIP, zBABIP is historically the better predictor. For all players with 50 PA in both 2020 and ’21, 2020 zBABIP is closer to 2021 BABIP than 2020 BABIP for 65% of players. Historically, the best predictor of actual BABIP, again using only these two stats, is a linear combination of 0.9 zBABIP and 0.1 actual BABIP.

Last season is still a small sample, but it’s at least interesting to look at 2020’s overachievers and underachievers.

Running 2021, I did run into an odd hiccup: zBABIP was suddenly overestimating actual BABIP for the league as a whole, something I had not come across before. I ran a number of tests to see if there was a particularly type of player who zBABIP was now overrating, but I never found any significant difference among hitters based on power, level of ability, groundball tendencies, contact rate, etc. In other words, it’s evidence that across the league, players are getting fewer hits from balls hit the same way in the same direction than in past years. My hypothesis, which I will revisit at the end of the year, is that we’re seeing the effects of the slightly deadened ball.

I also took the opportunity to look back at past Aprils and see if there is a similar discrepancy between zBABIP and BABIP in past Aprils, possibly due to early-season weather. I found no such discrepancy. This will be something to review as the season progresses.

Sadly, Mercedes, one of the most fun breakouts this year, appears on the overachiever list. While he’s hitting for good power, and that’s likely to continue, there’s a lot of air in that .373 BA to deflate. Trout naturally appears on this list, something that should be expected when a hitter has a BABIP over .500. The good news is that even with the largest discrepancy between zBABIP and BABIP, he still has the best zBABIP in baseball, at .365. Barnhart, while an overachiever, still has earned a high early-season BABIP thanks to being a line drive machine. (The league as a whole has a .622 BABIP on line drives, a .227 BABIP on grounders, and a .122 BABIP on fly balls.)

Two breakouts this season, Lowe and Winker, appear on this list, which is good news for their teams and fantasy players who have them on their roster. There was also quite a lot of meat behind Buxton’s 2021, earned before a hip injury put him on the shelf for a possibly extended amount of time. And while you probably shouldn’t be bullish on Quinn overall, there’s at least a good reason to think he can hit better than a pitcher, as damning with faint praise as that is. Juan Soto just misses the list, with a zBABIP about 60 points better than his actual BABIP, which would give him a season far more in line with expectations.

There’s a real limit on BABIP ability at the low end. I’ve found that historically, BABIPs below .230 or so have minimal predictive value. This is unsurprising, as pitchers, who are very rarely selected for their offensive talents, historically have a BABIP in the .210 to .230 range (.213 in 2021). Even Randy Johnson, as awkward a hitting pitcher as I can remember, had a .234 BABIP for his career. Bob Buhl, a pitcher so incompetent offensively that he once had an 0-for-72 streak, still managed a .162 BABIP. Albert Pujols, meanwhile, just missed the top 15 (.262 zBABIP vs. .176 BABIP), meaning that there’s a lot of truth to a complaint that the Angels released him for basically the same performance they were happy to plug into the middle of their lineup for several years.

As for those still active, there’s hope for Carpenter! He’s nearing the end of his career, but his offensive numbers shouldn’t be quite this poor, no matter how defensive shifting is involved. With the zBABIP, Cabrera’s line looks more like his unimpressive recent seasons rather than that of a bad pitcher. And the stats suggest that the long leashes for Tucker and Bell have ample justification.

A .194 zBABIP isn’t a prediction for Sanó, but it is evidence that there really is something wrong with him this year, more than just the sore hamstring. He’s lost a shocking 10 mph of exit velocity and half his overall hard-hit rate, and zBABIP isn’t an outlier, as Statcast’s xBA thinks he only “deserves” a miserable .152 BA this year based on his performance. Seeing Suárez on a list like this should concern the Reds: He may not be as lousy as his .156 BABIP suggests, but he still ought to have a very low batting average this year so far. The only silver lining for his 2021 is that he’s played somewhat better defense at short since his two-error Opening Day performance.

In chat recently, I expressed the opinion that Pache would probably seize back playing time from Guillermo Heredia before the season’s over, but given that he hasn’t been that much better than his actual BABIP, maybe he’ll need more extensive time in the minors. Since being recalled, he hit a home run in his first game back on the major league roster but has gone 1-for-23 since.