In this morning’s blog entry, Buster Olney discusses the Blue Jay’s signing of Jose Molina. Molina spent the past 2 seasons in pinstripes and Olney gives some pretty interesting numbers, as far as the how Yankee pitchers did with Molina behind the plate (compared to Jorge Posada, Kevin Cash, and Francisco Cervelli):
Check out the ERAs for Yankees catchers in 2009. The number in parentheses is innings caught:
Jose Molina: 3.31 (356 2/3)
Francisco Cervelli: 3.43 (241 1/3)
Kevin Cash: 3.49 (67)
Jorge Posada: 5.02 (785)
By these numbers, there is reason to believe Yankee pitchers simply pitch better when Posada is not behind the plate (or, at least they did in 2009). Those numbers can be a bit deceiving, however.
First, there are obviously the same flaws with Catcher ERA as there are with ERA in general. Namely, it allows things that the pitcher can’t control (and certainly the catcher can’t control), like infield and outfield defense, to impact the statistic.
Second, if you refer back to Posada’s career Catcher ERA, as shown here in a post back in June by Ben of River Ave Blues, you’ll see that 2009 is really an outlier. Despite Posada’s advancing age, it’s hard to imagine that he simply can no longer call a game. Age certainly will impact Posada’s arm strength and his flexibility behind the plate, which could lead to a decrease in thrown out runners and an increase in passed balls, but those things only have a very small impact on a pitcher’s ERA. And both of those skills have remained fairly consistent for Jorge (he’s remained average at throwing out runners and he’s always allowed a lot of passed balls). I think you could make the case that Molina frames pitches better than Posada, but again, that really could maybe lead to a few extra strike calls, if that. Not to mention, if that really does make an impact, then it just further supports my case for robot umpires – a strike is a strike, no matter how it’s caught.
Third, if you remember back to the spring last year, Posada caught a couple of games – one by Chien-Ming Wang in particular – where the Yankees absolutely got shelled. I think it’s pretty tough to argue that the pitching incompetence in those contests is entirely to blame on Posada.
Lastly, in general you would expect that the Catcher ERA be better for the defensive-minded backup catchers, since they are often assigned to catch the better pitchers, when presumably not as much offense is needed. In 2009, there was a stretch of time in May when Cervelli pretty much became Sabathia’s personal catcher. Very rarely will you ever see a backup catcher get used primarily with a 5th starter type, however.
Obviously Posada is not a great defensive catcher, but he is a great offensive catcher and it behooves the Yankees to keep him behind the plate as long as his defense is passable. Personally, I think that Catcher ERA doesn’t really tell us anything about a catcher’s ability, but it will, of course, still warrant paying attention to – at least until someone better develops a statistic to help measure a catcher’s defense and game-calling ability.