After a year's absence, the Smile is back in Tampa Bay. Carlos Pena lit up the Rays with his contagious smile and no-doubt home runs from 2007-2010, but by the end of that time, many of us were ready to let Pena go. He was on the wrong side of 30, his power had dropped off considerably in 2010, his defense wasn't what it used to be, and the over-shift had wreaked havoc on his batting average. Pena was looking for a $10 million salary, and considering the trend of his career, the Rays wisely decided to pass.
One year later, though, and our tune has changed. Pena bounced back slightly last season, with his average creeping back up to .225 and his extra base hits total increasing from 46 to 58, and the Rays signed Pena this off-season for $7.5 million to much fanfare. It's tough not to love Pena and his happy-go-lucky attitude, but he's a year older and his offense was helped last season by Wrigley Field and National League pitching. Have we already forgotten how painful it was to watch Pena in 2010?
We know Pena will have a low BABIP and batting average due to the shift, and that he will both strike out and walk liberally. His defense is likely slightly below average at this point, so Pena's value this season will hinge in large part on A) how much power he still has, and B) his ability to hit left-handed pitchers. As Jon pointed out recently, Pena's performance against lefties has declined each of the past three seasons, leaving his future in doubt.
So why has Pena declined? Are there any specific reasons we can point to? Let's take a look.
Bat Speed / Cheating On Fastballs. In trying to find some rhyme or reason in the PITCHF/x data to explain Pena's decline, I've come up with nothing conclusive. One of our initial hypotheses was that Pena had begun cheating on fastballs as his bat speed slowed down (I believe this was Glass's idea), but I can't find anything in the data to back this up. Sure, he swings and misses a ton, but his whiff rate on fastballs and change-ups has not gotten noticeably worse over the past three seasons. He has been whiffing on around 20% of the fastballs he sees in every year from 2008 to the present, and his change-up whiff rate has stayed relatively static around 40%.
In other words, we should keep an eye out to see if Pena's bat speed has slowed down or if it looks like he's priming his swing early, but this doesn't seem to be a cause for concern.
Pulling the Ball. What about this whole pull-happy thing? Has Pena been pulling the ball more often in recent years, driving the ball less often to the opposite field? Not exactly.
Overall, Pena hasn't become any more or less pull-happy in recent years. He's not going to the opposite field very often, but no less often than he was back when he was a dominant hitter (2008, 2009).
Ground Balls. Pena's offensive decline back in 2010 can be tied almost entirely to one factor: ground balls. Pena stopped making solid contact back in 2010, and his ground ball rate jumped up to 45% when he had averaged around 30% over the previous two years. These ground balls came at the expense of fly balls, giving Pena fewer opportunities to get extra base hits and home runs.
Last season, Pena managed to improve things. He lowered his ground ball rate to 37.5% -- still higher than it had been in 2008 and 2009, but similar to his ground ball rate in 2007. This seems to be a successful range for Pena (his career average is 37% grounders), but if we see his grounder rate sneak up above 40% again, that's a problem.
Are pitchers attacking Pena differently? Pitchers haven't changed their pitch selection against Pena over the past few years; he's still seeing around the same percentage of each off-speed pitch, so it's not as if he's all of a sudden seeing more two-seam fastballs or change-ups than ever before. And his decline can't be tied to his success against any one pitch, as his whiff rate for each pitch has remained relatively static as well.
Instead, I'm curious how much of an effect pitch location has had on Pena's success:
Notice how over the past three years, pitchers have focused more and more on the outside corner against Pena. They've also started focusing lower and lower in the zone.
I'm not sure if any of these changes have had anything to do with Pena's decline, but when you take all these variables together, they begin to paint a picture that makes sense. Pena has continued to pull the ball at the same rate as in the past, but pitchers are pitching him down and away much more often. This could be one of the reasons for the spike in his ground ball rate in 2010 -- just look at how many away pitches he swung at that year -- as he's refused to go the opposite way more despite seeing a preponderance of pitches on the outside corner.
There's no evidence right now that suggests that Pena has been cheating on fastballs recently, or that he's struggling any more than normal against off-speed pitches. Instead, it looks to me like his decline is the result of...well, exactly what you'd expect from an aging slugger: he's not hitting the ball as consistently hard as he used to. Pitchers are throwing him outside frequently, he's getting older, and the shift is eating up the majority of his grounders.
As much as I've harped on Pena's negative attributes in this piece, he should still be plenty good this season. He'll walk a ton and hit for power, and it's likely that his BABIP will more be closer to .260 than .220. Even if his power continues to decline, he can still be worth +2 wins by posting a wOBA around .340. That's a doable benchmark, and one that Pena could very easily surpass.
Remember, the Rays signed the 2012 Carlos Pena -- not the 2009 version. There are plenty of question marks surrounding him this season, so let's keep our expectations tempered. He doesn't have to hit 30+ home runs to be a successful signing; if he can perform like he did last season while maintaining an ISO above .200, I'd consider that a win.