Matt Kemp’s Historically Bad Month (for Him)

There’s something beautiful about an empty canvas because of its potential. The painter can turn it into literally anything — anything from a masterpiece to utter crap. The painter can make mistakes. She can paint a miserably bad portrait, yet still have time to amend it, perhaps creating an entirely different work — a different and better portrait, the ugly original buried deep beneath several layers of paint. The final product is a marvel, though the journey there was not smooth nor seamless.

Or right from the start she can paint the perfect landscape. And that’s great, except she continues to paint until it is no longer the masterpiece it once was but a mess of dimensionless color, unrecognizable and void of merit.

Such are the stories of the seasons of MLB hitters. A player can suffer a miserable April — the ugly portrait — yet slowly build up to a respectable end-of-season stat line. Conversely, a player can have a monstrous April — the perfect landscape — yet watch it slowly fall apart over the course of the next five months.

I’d like to focus on the prospect of the latter. It’s easy to get excited about a hot April because it’s much more obvious, whereas a hot (or cold) August, masked by four months of performance, can go unappreciated or unacknowledged. It’s not quite August, but even some May performances have gone, from one man’s perspective, largely undiscussed.

I originally intended to measure the largest drop-offs in weighed runs created (wRC+) from April to May for all National League outfielders with at least 50 plate appearances in each month (as of May 19 games). Rather, it snowballed into a full-blown investigation of Matt Kemp, our most egregious offender, whose wRC+ dropped from 132 in April to 21(!!!!!) in May.

This may or may not surprise you: Kemp is struggling through the worst month of his career (his abbreviated 2006 excluded) in terms of wRC+, and it’s not even close. Given his inflated batting average on balls in play (BABIP) in April, there weren’t too many directions to go except down. But what Kemp owners missed in April, and still miss now, is power; in that sense, Kemp has nowhere to go but up.

Kemp owns a career 217 wRC+ on fly balls. His 2015 fly ball wRC+: 30. Thirty. That’s bad. Alberto Callaspo has a better fly ball wRC+. Kurt Suzuki has a better fly ball wRC+. If there were ever a candidate for positive regression in the power department, it’s Kemp and his fly ball wRC+.

Still, his fly ball rate (FB%) has declined each of the last four years, bottoming out at a career-low 29.7 percent and creating perpetually smaller margins for home run power. Moreover, not all fly balls are created equal. Pull-side fly balls bode well for power, yet he’s hitting those at a career-low rate as well, reminiscent of his injury-plagued 2013 campaign. Instead, the fly balls are heading to the opposite field, where fly balls traditionally float harmlessly into outfielders’ baseball mittens. (In other words: shallow pop flies.)

Indeed: many shallow, easily playable pop flies. This isn’t necessarily a surprising or unique result; most fly balls to the opposite field are shallow pop flies, and understandably so. But, of course, he’s hitting them at a rate secondary to only his miserable 2013 — but even back then, he still hit more oppo line drives. That says a lot.

The man who once made a living feasting on fastballs now lets fastballs feast on him. Whether you ask FanGraphs or PITCHf/x pitch values, Kemp has recorded a negative value on them for the first time in his career. I think there’s a two-way correlation here: his slow start explains his limited damage against fastballs, yet his limited damage against fastballs explains his pronounced struggles.

Said struggles can perhaps be explained by pitchers testing his patience more than usual. His 44-percent zone rate (Zone%, per PITCHf/x) is a career-low, and, unsurprisingly, his overall swing rate stands at a career-high, more than six ticks above last year’s rate. He’s actually making his most contact on swings since 2009, thus helping his strikeout rate a bit but also explaining the lack of authority with which he has put balls into play.

The struggles are real for Kemp, and while he’s an obvious bounce-back candidate in the power department, his batted ball profile and plate discipline are discouraging. The sabermetric community talks a lot about metrics “stabilizing,” so it’s good to point out that most ball-in-play measures aren’t statistically reliable for probably another month or so. Still, we’re getting there, and it’s not looking good. Meanwhile, the suffocated walk rate drags down Kemp’s value no matter what kind of league you’re in. Sub-.300? Yikes.

It would be foolish to give up on Kemp entirely this early on. I fondly remember many of his suitors growing impatient with him last year despite a much more tolerable slump. But this is different. I don’t know if you’re wise to sell, but I wouldn’t blame you. Kemp painted a fairly decent self-portrait and promptly threw a bucket of red paint at it. It’s anyone’s guess what he’ll do with the canvas now.