Jake McCarthy Fights the BABIP Monster

What a wild ride it’s been for Jake McCarthy the past three seasons. In 2022, he finished fourth in NL Rookie of the Year voting, seemingly the right fielder of the future for the Arizona Diamondbacks. It wasn’t the kind of performance that would make anyone think that he — and not Corbin Carroll — was Arizona’s franchise player. But it was the kind of performance that could tempt inveterate contrarians into saying, “You know, Carroll gets all the attention, but McCarthy is the one who really makes this team tick.”

Then, in 2023, McCarthy was total buttcrack. He barely kept his head above replacement level as he lost playing time to Alek Thomas, Pavin Smith, Tommy Pham, and a partridge in a pear tree. Then, because when it rains it pours — even in the desert — McCarthy suffered an oblique injury that kept him from playing any part in the Diamondbacks’ run to the World Series.

But in 2024, he’s reclaimed his rightful place in the lineup, and he’s hitting .303/.375/.451. With almost two months left in the regular season, he’s set new career highs in games played and WAR. All is well once again.

Or, instead of reading those three paragraphs, you could just read this table and intuit the narrative on your own:

Say, what’s that column all the way over on the right with the numbers highlighted? Oh no, we’re going to talk about BABIP.

Well, first we’re going to talk about Austin Jackson. In December 2009, the Detroit Tigers took part in a three-way trade with the Diamondbacks and Yankees that sent star outfielder Curtis Granderson to the Yankees. It seemed like a drag at the time. Granderson was one of the Tigers’ best players, and such a nice guy he was really hard to hate, even in Yankee pinstripes.

But even though Granderson posted two 40-homer seasons in his first three years in New York, the Tigers didn’t have to mope for long. Jackson, the prized Yankee outfield prospect, took over in center field and immediately turned into We Have Curtis Granderson at Home: .293/.345/.400 with 27 stolen bases for a no-sweat 4.1 WAR season that arguably should have won Jackson AL Rookie of the Year.

(The Tigers also acquired a young pitcher named Max Scherzer in this trade, which I imagine helped smooth things over with anyone who still missed Granderson.)

What we didn’t appreciate at the time was Jackson’s .396 BABIP, which is the ninth-highest single-season mark in history for a qualified hitter in a 162-game season. It’s not like Jackson went straight into a tailspin after that — he was also very good in both 2012 and 2013 — but he didn’t quite turn out to be the next Granderson after all.

And it’s not like we didn’t know this at the time. Here’s an article from August 2010 on FanGraphs dot com by Wisconsin baseball legend Jack Moore, examining how much of Jackson’s stratospheric BABIP was legit and how much looked like luck.

Estimating those inputs — luck versus skill — makes a big difference when you’re talking about BABIP. A 50-point swing in BABIP is a difference of 11 or 12 hits in the number of at-bats McCarthy has had in each of the past two seasons. That’s about 40 points’ worth of actual batting average, or the difference between McCarthy being trade fodder and a borderline All-Star.

Let’s start by examining whether McCarthy has made gains outside of balls that are recorded by BABIP. In other words, how productive is he on home runs, strikeouts, walks, hit-by-pitches, and various interferences. What’s the opposite of batting average on balls in play? Batting average on balls out of play. I desperately wanted to call this little section “BABOOP,” but that’s not entirely accurate, because most of these events aren’t batted balls, and I’m measuring more than batting average, and… you know what, to heck with it:

McCarthy is actually walking slightly less than he did last season, but he’s also chasing less, missing less, and striking out less. And that has to be an intentional adjustment: Last year, McCarthy swung at the first pitch 38.5% of the time. This year, he’s swinging at the first pitch just 31.0% of the time. And he seems to be making better contact:

If you look at McCarthy’s xBA, it does look like he was lucky in 2022 but actually good this season. Which brings up an important point that’s peculiar to McCarthy.

Remember that xBA only factors in a batted ball’s launch angle and exit velocity, but not horizontal placement. And it also doesn’t factor in that if you were to build a hitter in a lab with the object of having a high BABIP, the product would look a lot like McCarthy. (I don’t know why you would, but hey, it’s not my lab.) McCarthy is a left-handed groundball hitter (48.4% career groundball rate), and also one of the fastest players in the league (97th-percentile sprint speed). He’s also impossible to shift; out of 209 players with at least 300 PA this season, McCarthy has the 169th-highest pull rate. And that spray tendency only gets more extreme if you narrow the sample to grounders: McCarthy is 191st in pull rate among the 222 players who have hit 80 or more grounders this season.

And while McCarthy is definitely hitting the ball in the air more — his GB/FB ratio is 1.32, up from 1.86 in 2023 — that’s only in relative terms. He’s still comfortably in the top half of the league for groundball rate. He also isn’t hitting it particularly hard; McCarthy is in just the fifth percentile for EV50 and the second percentile for hard-hit rate. On line drives, the lack of hard contact is especially pronounced. McCarthy’s BA-xBA on liners is .099, which is 17th-highest out of the 357 batters who have put 100 or more balls in play this year. McCarthy’s hard-hit rate on line drives is just 38.6, which is 29th-lowest among that same group.

But just getting the ball in play is half the battle, I guess. If there’s one thing McCarthy is actually exceptional at as a hitter, it’s making contact, particularly against fastballs. McCarthy is one of just 26 players who’s seen 150 or more four-seamers this season and has a whiff rate of less than 10%, and his performance against fastballs has been a major driver of both his slump in 2023 and his rebound this year.

McCarthy is among the league leaders in batting average and contact rate, but at the other end of the leaderboard in pull rate and bat speed. And having stared at a bunch of those leaderboards, two kinds of hitters share McCarthy’s traits. First, there are the absolute top-end bat control guys: Steven Kwan, Mookie Betts, Luis Arraez. The post-integration BABIP leaderboard puts Rod Carew, Ichiro Suzuki, and Wade Boggs in the top 10, and two Derek Jeter season in the top 25.

The other kind of player who hangs around this end of the leaderboard is less flattering: It’s singles hitters whose bat speed has completely gone. Which illustrates how perilous the tightrope is for a hitter like McCarthy, who doesn’t have 80-grade cat-with-Jedi-training hand-eye coordination like Ichiro or Betts. When everything goes right, he can be one of the best on-base guys in the league. But everything has to go right.