How David DeJesus Gained a Platoon Split

From David DeJesus‘ 2003 debut through his 2010 season, the versatile outfielder hit 90 wRC+ (1175 PA) against left-handed pitchers. Since then, DeJesus has mustered a lulzwut 29 wRC+ (327 PA) against lefties. Despite his one-sided floundering in the past three seasons, DeJesus managed to procure a three-year contract extension from the Rays.

Because we’re smart, you and I, the first thing we might notice about DeJesus’ platoon split is the enormous drop in BABIP in the previous three years:

Span	PA	BB%	K%	BABIP	wOBA	wRC+
2007-2010	744	6.9%	12.2%	.310	.314	87
2011-2013	308	7.1%	21.4%	.204	.216	29
ShH	308	7.1%	21.4%	.310	.284	79

This is one of those tricky areas where 308 plate appearances don’t seem like such a small thing, mostly because it’s spread across three seasons. So I’ve added a Should Hit (ShH) calculation that supposes his previous BABIP levels will return, but that his other stats — his walk, strikeout and homer rates — will remain the same. Even given that generous BABIP bump, we can see there’s something wrong with DeJesus’ effectiveness against lefties.

Let’s dig deeper.

Why does DeJesus’ platoon split matter? The Rays committed a very un-Rays-like amount of money to him. If and when the Rays pursue free agent outfielders or first basemen, they tend to search the low-cost scrap-heaps, at least since the ill-fated Pat Burrell signing. And while DeJesus was never really a free agent, they did have the option to pay $1.5 million to make him one.

I suspect Rays will squeeze as much value out of DeJesus’ contract (which, we should note, is modest or average by most team’s standards) and Joe Maddon will give DeJesus a chance, much like he did with James Loney, Casey Kotchman and Jeff Keppinger, to prove he can play against non-elite lefties (against righties, in Kep’s case). When it comes to facing lefties, the Rays already have a 67 wRC+ hitter in corner outfielder Matt Joyce. Adding a second to the mix hurts Maddon’s usually very flexible playing time schemes and plans.

So what has changed that might have caused DeJesus to suddenly become lefty-inept?

The Tableau above shows his ball, his called-strike and his whiff rates. Notice which one has changed the most significantly: the whiff rate. Spiking from 4.3% to 7.9%, an increasing swinging strike rate suggests DeJesus’ BABIP problem is more than just hard-luck bounces. The most expedient way to a bad BABIP is bad contact, and that seems to be part of the brew here.

Click, if you will, the “Swinging Strike” option on the right. This will isolate his swinging-strike results in the scatter plot strike zone (holding CTRL will allow you to select multiple pitch results). The results are somewhat slim here, but it does appear DeJesus has been biting more on low-and-away pitches than in years past. These appear to be largely breaking pitches.

NOTE: Because of the fickle algorithms for historical PITCHf/x data, the pitch-type data is not very useful in comparing across the two eras.

Decreases in out-of-zone contact come with aging, and when they do come, they come fast and hard (see “Hitter Aging Curves: Plate Discipline”).

Click also, if you will, the “Called Strike” pitch result on the right. Much in confirmation of Jeff Sullivan’s and Jeff Zimmerman’s recent findings, DeJesus has seen fewer egregious “lefty strikes” of late. I doubt this feeds into his struggles (quite the opposite, if anything), but it’s a cool thing to notice confirmed on a micro level.

If we expand our scope to analyze plate-appearance results instead of pitch results, we begin to see a much bigger difference in performance:

His once-decent strikeout rate (14%) has ballooned to 25%. Again, this is incredibly troubling. Quite possibly, it’s a sign of a bad adjustment or change or — more ominously — aging or decreased bat speed. Strikeouts went from his fourth-most-common PA result against lefties to his most common result.

His single percentage (17%) slid about five points (12%), which I tend to see as a BABIP, hard-luck change. But when his doubles (4% to 1%) and homers (1.2% to 0.2%) decrease, too? And his groundout and line-out rates stay the same? It looks much more like a systematic problem. Take an isolated look at DeJesus’ doubles. His recent extra base hits have almost exclusively come on pitches in the heart of the zone, but the earlier plot shows DeJesus slapping doubles off pitches farther outside the zone.

Has DeJesus changed his stance? Has he closed himself off more against lefties? From what I’ve seen, I can’t say much has changed. At most, it looks like he might be standing a little taller at the plate, but even that’s hard to tell. He might also be a half step closer to the plate, but I’m not even sure that would noticeably affect his vision against lefties:

2013 DeJesus:

2010 DeJesus:

The video of DeJesus (White Sox vs. Royals) from 2010 shows some of what has been missing in his swing lately: The ability to go the other way against lefties. Is this a skill a player can lose over time? I imagine a player can lose any skill. Few players add skills in their careers, though. But if the Rays can find some method of correcting DeJesus ‚ bringing him back to his mid-to-high 80s wRC+ against lefties — I think it will come by way of getting him to handle those outside pitches again. Perhaps moving him away from the plate a half step will make the down-and-away pitches look less tempting (though this might conceivably also hurt him in efforts to take more pitches the other way).

The average center fielder and left fielder in 2013 reached a 99 wRC+. If DeJesus can muster an 85 wRC+ against lefties, he puts himself in serious contention for a full-time outfield position in Tampa Bay. And that’s not just because his defense is acceptable, but because he can complicate reliever usage for opposing managers.

There are intelligent arguments against the DeJesus extension. But don’t be surprised if the Rays and their PITCHf/x brain trust find some way to make DeJesus into a valuable regular. There might still be a chance to salvage his abilities against lefties.