Another Varitek data point

A month and a half ago I wrote a piece challenging the long-held conventional wisdom that Jason Varitek was helping the Sox pitchers' ERA. It got linked and generated a fair amount of traffic, as well as a lot of disagreement. Well, this week, David Laurilia interviewed John Dewan at Baseball Prospectus and the topic of Varitek's defense came up:

DL: Looking at the book, I was surprised to see how poorly Jason Varitek rated in Earned Runs Saved over the past six seasons.

JD: Yeah, that actually surprised us. Jason Kendall is near the top, Pudge Rodriguez is near the top, and we were a bit surprised by Jason Varitek. But the bottom line is that his Catcher ERAs — and we do an adjustment based on park factors, and in his case it doesn't matter as much, though historically park factor adjustments are important for a guy like Mike Piazza especially. But Jason Varitek just consistently, when you looked at how he compared with other Boston catchers, he didn't do as well. And our system not only compares against Boston catchers, but it will take into account pitchers who pitched for the Red Sox, and how they did when they were traded in midseason and caught by catchers on other teams. There are a variety of factors that come into play, and Varitek did surprise us by not coming out as well as we had expected...there are still so many components of what a catcher does, like working with a pitcher and working with the team, and those are areas where both Ausmus and Varitek are team leaders. Both have aspects to what they do that we don't know how to measure yet. So if I were a push-button manager, neither of those guys would play for me. But the managers who are managing those guys know a little bit more about them, and what other aspects are important. What I would tell [Terry Francona] is that it doesn't look like [Varitek] is helping his pitchers' ERAs. If that's what you think is happening here, it's not.

Just because John Dewan says it doesn't make it so, but it provides another data point. Someone else looked at the data and came to the same conclusion. I'd love to see someone try to make the case that Varitek is helping his pitcher's ERAs, but I don't know how you'd do that - the data seems to strongly suggest the opposite.