Adrian Gonzalez has been more valuable this year than last. If I told you that, you wouldn’t believe me, right?
This year he’s hit .261/.335/.470 and last year, in the same ballpark, he hit .301/.362/.500. There is no way he could be more valuable this year, right? Well, wrong, at least kinda. This year his WPA (win probability added, calculated by fangraphs) is 2.04. Last year it was a much lower 1.02. You might wonder how the hell that happened. It’s all about clutch performance. Gonzalez’s “clutchiness” this year is 1.31 (4th in all of baseball!) which is a complete turn around from the -.64 that he put up last year. Before we go any further, let’s look at how these things are calculated.
WPA is just win advancement minus loss advancement. A player gets credited for positive events and debited for negative ones. Say, a 2 run single to in the game in the 9th is worth .4 wins. The player is credited with .4 win advancements. An out in the first inning trailing 5-0 is worth -.02 loss advancements. The player is “credited” with -.2. Add all of these up at the end of the year to get WPA. Just as a note, I made those numbers up.
Clutchiness is basically how many wins the player added over what would be expected. The formula is WPA – (OPS Wins * pLI). OPS Wins is .025 * (1.7 * obp + slg – 1) * PA. The numbers are also park adjusted. pLI is leverage index per plate appearance. Usually for hitters it’s around 1.
Here are Adrian’s PA’s sorted by leverage index. This is what he has done in his 5 most crucial PA’s:
Double, fly out, double, double, sac fly. Pretty clutch, ey? In those 5 PA’s his WPA is .795. Last year in his 5 most critical PA’s he singled, walked, struck out, singled, and GIDP for a total WPA a .292 … a pretty large difference when we’re just talking about 5 times at the plate. Anyway, this is just cherry picking, as you obviously look at all PA to determine this stuff.
The merits of WPA (and “clutchiness”) are something that certainly could be discussed, as could the implications of this on any evaluation of Gonzalez. I don’t really think he’s been “better” this year. He’s just leveraged his performance so that, in a sense, he has provided more value, by WPA’s standards, to the Padres. Going forward, you’d probably regress his clutch performance a long way toward average and evaluate him like that. Afterall, how does a player go from -.82 clutchiness from 04-06 to +1.31 clutchiness in 07. There’s just a lot of random flucuation involved.