It is convenient to break down the Red Sox’ team ERA based on which catcher is behind the plate — 2.07 with Jason Varitek, 6.14 with Jarrod Saltalamacchia — and conclude that Varitek is far superior at handling pitchers.
But it wouldn’t necessarily be true.
Take it from Mike Scioscia, a catcher for 13 seasons with the Dodgers and the Angels’ manager for the past 12 years: Catcher’s ERA can be a telling statistic, but only if it is used correctly. And, too often, it is misapplied.
Scioscia has spent considerable time thinking about catcher’s ERA, which uses the ERA formula for pitchers but substitutes a catcher’s innings played for the innings pitched. For much of the past five seasons, Jeff Mathis and Mike Napoli served as the Angels’ catching tandem. Mathis, a .200 career hitter, always has been known for his defense. Napoli, who possesses middle-of-the-order power, is widely regarded as a below-average backstop. And catcher’s ERA seemed to support those characterizations. Since 2006, Mathis has a 3.90 catcher’s ERA, more than a half run lower than Napoli (4.47), who eventually was jettisoned in an offseason trade for outfielder Vernon Wells.
But Scioscia never put much stock in those aggregate numbers. Instead, he preferred to look at a catcher’s ERA with each individual pitcher to help measure the effectiveness (or lack thereof) of that particular pitcher-catcher relationship. As much as teams would like their pitchers to have success with any catcher, it is human nature that some batteries, like some marriages, work better than others, and the catcher’s ERA stat is one way to find out which of those relationships are built to last.
“I think it’s an absolute tool to evaluate a catcher’s performance with a pitcher, but it can’t be cross-referenced,” Scioscia said the other day. “It’s got to be really with that pitcher to get an idea of what is that catcher doing with that pitcher. You want analyze, why is this guy giving up a run a game more with this other catcher. Is it walks because of pitch selection? Is it hits? Is it stolen bases? Why is it happening that when this guy catches, this pitcher’s ERA is 5.30, and when this other guy catches, it’s 4.30? A guy might not be conditioned with one pitcher, but we don’t just stop and say, ‘Oh, he doesn’t catch this guy well.’ We want to know why. Why did Napoli walk more guys with this (pitcher) than Mathis? You want these guys to all be there for every pitcher.”
Along those lines, here is a look at each Red Sox starter’s career ERA with various catchers to whom they have thrown most often during their tenure with the Red Sox:
Varitek (3.49 in 85 games), Victor Martinez (3.24 in 27 games), Kevin Cash (3.83 in 9 games), Saltalamacchia (2.22 in 4 games)
Martinez (4.81 in 20 games), Saltalamacchia (4.63 in 7 games), Varitek (3.29 in 6 games)
Varitek (3.86 in 114 games), Martinez (5.48 in 15 games), Saltalamacchia (4.50 in 2 games)
Martinez (2.83 in 40 games), Varitek (5.26 in 20 games), Saltalamacchia (6.19 in 4 games), Cash (4.38 in 4 games)
Varitek (3.90 in 80 games), Martinez (5.47 in 12 games), Cash (3.81 in 5 games), Saltalamacchia (11.42 in 2 games)
A few conclusions: Beckett and Matsuzaka are clearly most comfortable working with Varitek, and over the past few weeks, the Red Sox have made certain to match them up with the 39-year-old captain. Lackey and Lester have similar degrees of success with multiple catchers, so they are seemingly good fits to work with Saltalamacchia as he continues to get comfortable behind the plate. Buchholz had tremendous success with Martinez, but he is still working on consistently duplicating that synergy with Saltalamacchia and/or Varitek.
But before we get too carried away, one other critical point: Scioscia also noted that catcher’s ERA, like any statistic, is reliable only if it is based on a large enough sample size. With Saltalamacchia, the sample size remains small. To conclude, based on three weeks, that Saltalamacchia is incapable of calling a good game would be akin to labeling Carl Crawford a lousy hitter because he’s batting .171 with a .462 OPS after 20 games. Yes, Red Sox pitchers had an 8.16 ERA over the season’s first four games with Saltalamacchia behind the plate. But in his last five starts, Red Sox pitchers have a 2.06 ERA. See? Small sample size.
Point is, catcher’s ERA can be a useful tool upon which to make judgments. But it’s usefulness must be kept in the proper perspective.