What to expect from Pettitte

Andy Pettitte’s decision to come back to baseball was exciting to say the least, but since he is a soon-to-be 40-year old who has not pitched in over a year, it would be wise to temper our expectations for the time being.  That being said, let’s look at the numbers and see what we can reasonably expect from Pettitte this year.

ERA- (2007-2010): 90, 105, 90, 77

For those unfamiliar, ERA- essentially compares a pitcher’s ERA to league average (100), so an ERA- of 90 is 10% lower than league average that year. As you can see, Pettitte seemed to show no signs of decline before he “retired”, at least according to ERA.  However, because ERA does not take into account defense and luck, let’s look at Pettitte’s FIP-, which only takes into account the things that a pitcher has near-full control over: strikeouts, walks, and homeruns.

FIP- (2007-2010): 88, 86, 91, 89

Here, Pettitte looks like a remarkably consistent pitcher, and 2008, which was his worst year according to ERA, is his best according to FIP. 2010, on the other hand, becomes about even with the other three years according to FIP, despite his low ERA that year. Still, there are no signs of decline from Pettitte, which is positive but surprising given his age. In fact, his K/9 of 7.05 in 2010 was his best since 2006, and better than his career K/9 of 6.63! We would normally expect an aging pitcher’s strikeout rate to slowly decline, but Pettitte was able to maintain a solid rate, and his average fastball velocity was virtually unchanged in his last three years.

If it were 2011, we may conclude from this that Pettitte, barring injuries, was poised for another solid but unspectacular season, making him a very solid #5 starter. However, it is not 2011, and we don’t know what effect Pettitte’s year off had on his level of talent. Because he initiated the deal with the Yankees, I have no doubt that Pettitte believes that he can provide value to the team this year. However, no matter how well he kept in shape since his departure, a year without facing Major League hitters and Father Time may not be kind to Andy.

Even if we assume that the year off had no effect on Pettitte’s talent level, he is still almost a year and a half older than the last time he pitched, and we would be foolish not to assume some regression from his 2010 numbers.  Pettitte was on pace for about 3.7 WAR (Wins Above Replacement) in 2010, so the maximum value we should expect from him is probably about 3.0 WAR, which would have made him the Yankees’ second-most valuable pitcher 2011. But add in his injury risk, his year off, and the likelihood of a more significant age regression, and Pettitte becomes a 1 or 2-win player in 2012. That is by no means useless, but with a deep rotation, I’m not convinced that Pettitte has a spot.

We will have to wait and see how Pettitte progresses in his preparation for the season, and if we find that his velocity has not decreased and his command is still good, then he could be a very valuable option for the Yankees. However, given his age and injury risk, expectations of a triumphant return should be withheld for now.