Did Curtis Granderson have a bad season?

No doubt contemplating his last strike out.

Here’s the good with Curtis Granderson: he’s a home run and walk machine. For the second consecutive season as a Yankee Curtis knocked in at least forty homers. That’s good. He continues to have a walk rate above 10%, also good. Now, here’s the bad: .226/.315/.477. That’s Curtis’ season batting line. There’s no doubt that the dude can mash. What’s not to love about a .252 ISO? But when did he turn into Adam Dunn? Last season Granderson managed comparable power numbers (better, actually) and did it with a .364 OBP. This year his OBP fell fifty points and he struck out 191 times, far and away a career record. What happened?

The numbers suggest two things. First, Curtis got lucky last season and unlucky this year. His .295 BABIP in 2011 was his highest with the Yankees. His .256 BABIP this season is the lowest of his career. The forty point drop will have an out sized impact on Granderson because he puts so few balls in play due to his strike outs and homers. That’s pure average that he’s losing, and the difference between a decent OBP and a bad one.

But luck isn’t the only factor. The numbers also suggest that Curtis is getting beat on the fastball more this year than last year, and swinging through curveballs. In 2011 Pitch FX says that Curtis was worth 21.1 runs against the fastball and was more or less flat against the curve. This year he’s been worth 8.4 runs against the fastball, which is still good, but a regression from his 2011 highs, but he’s been worth -5.3 runs against the curve.

A player who is less effective against the fastball and beatable with the curve is going to be a strikeout victim. Needless to say, Curtis is striking out 28.7% of the time this year, a career high. He’s also swinging at more pitches outside of the zone (27.3% this year versus 25.6% last year, according to Pitch FX) and making less contact across the board. Opposing teams know this. There is a formula for getting Granderson out. Throw curveballs. Sure, he’ll run into more than a few of them, and draw a ton of walks, but almost as often as he gets on base he’ll strike out. That’s a risk worth taking.

It’s also a risk that has payed off for the opposition. After putting up a monstrous 147 wRC+ in 2011 Curtis has come back down to Earth like a comet. His wRC+ this year is just 111. That’s still very good, but it is a disappointing figure for a player who only a year ago looked like he was poised to become one of baseball’s best.

It is unfair to argue that Granderson had a bad season. He produced a ton of runs in the middle of the Yankee lineup and had an above average offensive season despite his poor on base skills. However, he regressed tremendously. In 2011 Granderson was a 7.1 fWAR player. This year he’s just a 2.0 fWAR player. Part of that regression is because Fangraphs hates Curtis’ defense (Seriously, a -18.3 UZR? I don’t buy it!) but mostly it’s because of the strike outs.

The downside of all this sits entirely with the team. As far as Curtis has regressed this year he remains a solid option in Center Field. As a result, it seems unlikely that the Yankees would decline their team option on Granderson for 2013. Instead, the team will ante up for another season. Hopefully Curtis will continue to show the flexibility he demonstrated with Kevin Long last season and work to cut down on the strikeouts. Otherwise, 2013 may well be his last season in pinstripes.