The quasi-historical performance of DJ LeMahieu, and other BABIP thoughts

DJ LeMahieu, the player Gary Sanchez calls “the machine”, the Yankees’ big free agent signing. He’s known for great defense, prodigious hitting with runners in scoring position, and so on and so forth.

I’m not here to talk about that. I’m here to talk about a multi-year streak LeMahieu’s on—a streak that may not be totally noticeable until one delves into the data.

LeMahieu is one of about two dozen players that has yet to see an infield shift this year. In and of itself, that’s not that unbelievable. It’s still June, and while it’s probably too far into the season to say it’s early, it’s early enough that certain wonky things are still being worked out across baseball.

Of course, if you tab over to the 2018 shift data, you will find that LeMahieu saw zero infield shifts in 2018 too. Go back one more year, and there were no shifts against him in 2017. The last time LeMahieu came to the plate with infielders playing anything but straight up was July 31, 2016. The only player with a longer streak than LeMahieu is Dee Gordon, a batter with a completely different skill profile.

Gordon is a classic, light-hitting speed guy. His sprint speed is well above league average at 27.5 ft/s in 2019, whereas LeMahieu is actually a below-average runner. He hits the ball much harder than Gordon, with his average exit velocity more than seven miles per hour better than the Mariners infielder.

One of the things that sort of fascinates me about LeMahieu has been how BABIP dependent he is. I’ve written about this before, but now there are 250 plate appearances in 2019 that highlight that fact:

More than perhaps any other current Yankee, LeMahieu relies on BABIP to drive his positive outcomes.

Having moved into a post-Moneyball era in baseball analysis, what was once accepted as gospel has had to change to reflect new information. BABIP used to be seen as the best measure of luck that we had; a ball in play is subject to so many variables that a player running a particularly high or low BABIP was bound to see some fluctuation. Now, however, we know that BABIP is less a cause than a symptom. It is possible to sustain what would be considered an abnormally high BABIP if a player meets the right conditions.

Aaron Judge is a good example of this. While he puts so few balls in play because of his walks, strikeouts and home runs, Judge hits the ball harder than anyone in baseball. That means the balls he does put in play are just more likely to get through the infield. This quality of contact has allowed him to run a fairly high BABIP throughout his career.

LeMahieu runs a high BABIP too, but there’s a fair amount of information that shows it’s more sustainable than just being pure luck. First, he hits the ball fairly hard, with a 91.8 mph average exit velocity. More than just raw output, his batted ball velocity tends to be in a tighter band than the league’s.

LeMahieu’s average exit velocity is 91.8 mph, but the standard deviation of that EV is 12.6. Compare that to the 40,000-odd balls in play MLB wide this year, which boast an average EV of 86 mph and a standard deviation of 15.1.

This means that the batted balls off LeMahieu’s bat fit into a tighter band of EV than the MLB average, while also just being hit harder than most players. He’ll have fewer batted balls of 105 mph than some, but he’ll also have fewer 70 mph jam shots that really drag down your performance.

The second key part of why LeMahieu’s BABIP isn’t so lucky is his ability to put the ball all over the field:

Over the last three years—the same three years that LeMahieu has not been shifted on—this has been his spray chart. Find any pattern in these batted balls, go ahead.

Now compare it to a player who’s closer to the middle of the pack in shifts, someone like Paul Goldschmidt who sees a shift 12.5% of the time over the last three years:

Goldy is an all-world hitter who sprays the ball to all fields, too, but there is just a slight preference for pulling both in the infield and outfield. It doesn’t look like much, but it’s there, and it’s the justification for teams shifting against him more than one in ten plate appearances. That’s the margins of difference we’re talking about here. It takes a very slight pattern to make shifting worth it, but LeMahieu doesn’t even have that.

The changing attitudes around BABIP have been a great icebreaker into the changes in analysis of baseball overall. Ten years ago, we would have looked at LeMahieu’s BABIP and all assumed he was getting lucky, but he’s not. Being so tied to BABIP is still going to cause volatility in performance—just look at 2018—but LeMahieu’s combination of good raw hitting and hilariously spread batted balls means that there’s no cause to worry about BABIP itself. There may be volatility, but there’s no correction coming.