Posted Under: Stat of the Week
Last week we looked at a defensive statistic for catchers called Catcher’s ERA (CERA) which was meant to give baseball fans a better understanding of how a catcher altered a game by his defensive prowess behind the plate.
We learned, however, that CERA was not a dependable or reliable tool in our sabermetrics tool kit to properly evaluate catchers, but that all hope was not lost. It is surprising that there has not been more emphasis placed on developing statistics that evaluate the defensive capabilities of catchers because the pitcher and catcher are the two players that are involved on every pitch during every at-bat.
Strides have been made with statistics such as Stolen Base Runs Saved (rSB) and Passed Pitch Runs (RPP) which when combined according to FanGraphs can give us a better perspective of how good a catcher is at his job.
rSB looks at a catcher’s ability to save his team runs by both throwing out runners trying to steal and dissuading runners from attempting to steal because of their strong arms. It is calculated by The Fielding Bible and “measures how many “runs” a catcher contributes to their team by throwing out runners and preventing runners from attempting steals in the first place” according to FanGraphs.
RPP was developed by Bojan Koprivica of The Hardball Times and if you have the time, read his article on how he developed the model that determines how many runs a catcher is above or below average at blocking pitches in the dirt, it is pretty cool stuff.
For rSB and RPP you can look at this table provided by FanGraphs to determine where your catcher falls in terms of his defensive skills for each stat:
One last statistic I would like to see is a catcher’s ability to get the ball out when a runner is stealing. This would allow us to see how quick the catcher is to move his feet and start throwing and would eliminate the variability of the pitcher. Some pitchers aid their catchers in keeping runners close to the bag because of their pickoff moves (i.e. Andy Pettitte), while other pitchers such as Roger Clemens were notoriously slow to the plate and easy to swipe bags off of, no fault to the catcher at all.