I will start this little diatribe by saying I don't like Catcher ERA. I don't like the idea of it. All of the usual caveats for ERA are present- it is extremely luck influenced, it doesn't tell me how good the guy is at recording outs, and it doesn't tell me how big the sample size is.
So today's NYTimes article on Jorge Posada started my day on the wrong foot. Tyler Kepner writes:
With Posada behind the plate, the Yankees’ pitchers have a 6.31 E.R.A. The combined E.R.A. with Francisco Cervelli, Jose Molina and Kevin Cash is 3.81.
Let's start with sample size. Posada has spent 232.1 innings behind the plate this season.
Cervelli has spent 151.0, Molina 115.1, and Cash 67.0 innings. So the masterful trio have spent 333.1 innings calling pitches. That's 133% of Posada's time.
Of the roughly 163ER that have scored on Posada's watch, we have to consider that 27 of them came in just under 9 innings worth of Chien Ming Wang. Taking those out lowers "Posada's" ERA nearly a full run (5.49). Give him another 100 innings of the Yanks' average ERA (4.84) and he comes down to around 5.2. Not pretty, but not the misleading number that Kepner reports.
Conversely, Cervelli caught CC Sabathia at his best; Cervelli caught 32 innings against 6 ER while CC was dominating May and Posada was out. Toss those innings to Posada, the trio's ERA rises to 4.05 while Jorge's falls from 6.31 to 5.76. Does anyone think that Cervelli et al should be credited when CC is clearly on his game? If so, the Yanks should be spending millions on smart pitch callers rather than on high leverage arms.
On the other hand, I've been watching the news coverage of Pudge Rodriguez's march to the record for all time games at catcher. We all know first hand what an awful game caller he is. Maybe, as one poster postulated recently, maybe Posada has a pitch call pattern that other teams have begun to pick up on, either consciously or subconsciously.
Anyone want to help me watch the starts for the next couple of times through the rotation and chart the pitch type percentages with Jorge behind the dish vs. the backup? Maybe there's something to see there.