Count me among the Yankee fans who were thrilled when Andy Pettitte came back in 2012. One of the low points of my Yankee fan career was watching Pettitte put on an Astros uniform from 2004 through 2006. I was certain Pettitte was one of the Yankees who would play his entire career in pinstripes. I never blamed him for leaving. I was thrilled when he came back. For similar reasons I was shocked when Andy temporarily retired after 2010. He had something left in the tank. It just didn't make sense for him to call it quits. Andy came back in 2012, and showed that he could still pitch, that only his ability to stay healthy would keep him in check. Now that he's signed up for 2013, at the age of 41, what does Andy have left?
The answer is that it is unclear. Using just the eye test, Andy looks as dominant as ever. He put up an impressive slash line of 2.87/3.48/3.27 in 2012. He appears to have overcome his diminished velocity (Pitch FX says he averaged just 87.8 mph on his fastball last year) by mixing his pitches well to get batters out. The real question doesn't appear to be an ability to find a way to get batters out with a diminished arsenal, but an ability to stay healthy. Pettitte has been injured each of his past two seasons in the big leagues. Time isn't on his side.
Pettitte's age comparisons don't bode well for durability either. Baseball Reference says that for his career he is most similar to David Wells, Mike Mussina and Kevin Brown. Mussina and Brown never saw an age 41 season (although Mussina left at the top of his game). Of the three, only Wells played an age 41 season. For what it's worth, that season was pretty good. Wells pitched 195.2 innings with a 3.73 ERA and a 1.14 WHIP. I would take that from Andy in a heartbeat.
For my part, I believe that if Andy is healthy he'll be productive, but with a wide range of possible outcomes (anything from a sub 3 FIP to just above 4). Since 2006 Andy has seen his fastball diminish as a weapon, and he has responded by using his cutter and curveball more effectively. Those are pitches that can get batters out without requiring a lot of velocity, meaning that they will age better than a pure fastball. In that respect Andy should still be able to get big league hitters out. The question is health. Pettitte is an old baseball player, and while it is fair to argue that his 2012 injury was a fluke, it is also fair to point out that a younger player may have gotten out of the way or may not have suffered as severe an injury.
Older players are an injury risk. Success for Pettitte has to be defined in those terms. It is safe to predict that he will wind up on the DL at least once during the 2013 season. The question is what puts him there. I'm willing to predict that a prepared Andy, one who is not trying to come back mid-season, can limit his injuries to something manageable. In that regard, 150-165 innings of about a 3.85 FIP season seem justified as a forecast. It wouldn't be the Andy of old, but it would still be a valuable contribution.