The Redisappearance of Matt Kemp

Matt Kemp is in a funk. I’m not talking about the kind of funk endorsed by Sly Stone or Parliament. Kemp’s funk is more like the time a friend of mine left a chicken salad sandwich in my car over a hot weekend and it fermented into a noxious cloud of nauseating death-barfiness. Or funk metal.

I’m nearly certain the Dodgers didn’t originally expect to ever have Kemp on the roster in 2018. LA acquired him from Atlanta in exchange for Charlie Culberson, Adrian Gonzalez, Scott Kazmir, Brandon McCarthy, and cash — and if the the deal were to have occurred in 2012, with those names, it would have been a blockbuster. In the winter of 2017, however, Kemp wasn’t so much a player as a tax loophole, the maguffin in a trade that was primarily about teams aligning their year-to-year payrolls in such a way as to avoid luxury tax.

But a funny thing happened on the way to the luxury tax: Kemp became interesting. For once, one of those articles about a player looking amazing in spring training actually bore real fruit. Kemp showed up to spring training in excellent shape, having lost a non-trivial 40 pounds and gained a renewed interest in playing defense.

The homecoming to Los Angeles, after a lot of hurt feelings years ago, turned out to be a positive one. When Kemp slugged .561 in spring training while also exhibiting improved defense and a real effort to be a mentor to the younger players, he gave the Dodgers enough justification to keep him on the team as a role player.

Los Angeles struggled early. Kemp, however, did not. With one of the club’s top batting marks and the promise of better defense — or at least decidedly less-atrocious defense — fulfilled, Kemp received more at-bats. Unlike in previous seasons with Atlanta and San Diego, Kemp’s playing time in this case was earned on the merits of his play and not his reputation or salary. He started in the All-Star Game.

Since the All-Star Game, though, things have not gone well for Kemp. Standing at .310/.352/.522 when baseball took its midsummer respite, Kemp’s OPS has bled about 100 points in just a month, and he’s stalled at 1.1 WAR for the 2018 season. Neither ZiPS or Steamer are optimistic about a turnaround, projecting him to finish at 1.3 and 1.2 WAR, respetively, the primary difference between the two being playing time.

Before Wednesday’s 2-for-4 performance, Kemp last had a multi-hit game on July 23rd and now has hits in four of his last 19 games. Overall, he’s 5-for-58 from that date with only a lone double. The result? A .086/.191/.103 line.

So, what happened to Kemp’s 2018?

The first part is our old friend and noted batting average blackguard, BABIP. In his best seasons, Kemp maintained a high BABIP, which was largely justified by the more advanced data (though no Statcast at the time!). zBABIP is the BABIP estimator built into ZiPS, in a similar vein to xBABIP or Andrew Perpetua’s work.

Kemp had a .388 BABIP in March/April and a .416 BABIP in May, numbers that nobody should have expected to be maintained. In some way, his early-season numbers reflect the danger of believing small sample sizes when they correlate with the storyline, in this case a player who made a concerted effort to recapture his best days.

When comparing his seasonal BABIP to his predicted one from advanced stats, Kemp’s actually had the 2018 season overall that he’s deserved; he’s been no more unfortunate in recent months than he was fortunate early on, at least when talking about BABIP.

One thing that has, in fact, changed is that pitchers are simply less aggressive at giving Kemp fastballs to hit, especially in the more favorable counts where Kemp may be seeing dead-red. From Brooks Baseball, here’s Kemp through the end of May…

… and from the start of June through Wednesday night:

This is relevant because, during Kemp’s period of greatest success, from 2008 to -14, he was 181 runs better than average against fastballs according to FanGraphs’ pitch value estimates. Against everything else, that total stands at two runs worse than league average.

Kemp’s still hitting fastballs even now. Through the end of May, Kemp batted .418 when hitting a fastball with a .758 slugging percentage. Those numbers have remained excellent, to the tune of a .377 batting average and a .689 slugging percentage. For his career, those numbers are .328/.601. Matt Kemp remains a hitter who lives or dies on the hard stuff and whose success in 2018 has been largely driven by seeing and hitting a lot of fastballs; taking a few of them away from him has a larger negative effect on his performance than for most hitters.

Even in the midst of a .173/.264/.280 second half, Kemp’s at .345/.621 against fastballs. Since his start in the All-Star Game, he has seen 208 pitches (as categorized by Brooks Baseball) that weren’t fastballs or sinkers. He’s gotten exactly one hit off those 208 pitches, a solitary single off a curve thrown by Yusmeiro Petit.

Every team in baseball pays attention to this kind of data, and for now, Matt Kemp is solved. Baseball is a game of continual adjustments, and as great a story as Kemp’s re-emergence has been, if he’s unable to adjust when the pitchers do, he may find himself out of baseball very quickly.