Statcast data which tracks pitcher time to the plate, catcher pop time, and base runner times will be immensely helpful in determining which catchers have saved runs and which catchers have just been around when their pitcher saved runs. rSB and SRAA/TRAA are good metrics, but they aren’t able to unpack everything.

While this seems like it should be the easiest component to measure, we still remain uncertain about measuring the catcher’s role in SB prevention. Their stats offer an indication, controlling for other factors, of how much more often a given catcher allows a stolen base or allows a runner to takeoff in the first place. This stat measures, in runs, how a catcher compares to the average catcher in terms of preventing stolen bases, accounting for the fact that the best way to prevent a steal is to prevent the runner from attempting it.īaseball Prospectus has recently debuted Swipe Rate Above Average (SRAA) and Takeoff Rate Above Average (TRAA) which communicate the same idea in percentage form. First, available on FanGraphs and elsewhere, you can find rSB, or the DRS-based Stolen Base Runs Above Average. There are two major public attempts to address this issues. This means we cannot simply judge a catcher base on their number of steals allowed or their caught stealing rate. For example, studies have shown that the pitcher and runner play important roles in determining the probability a steal attempt occurs and how often that attempt will be successful. What we want to be able to do is measure how a given catcher compares to an average catcher in terms of allowing stolen bases, while controlling for the parts of base stealing he cannot control. The idea of preventing stolen bases is the easiest to consider, but it remains difficult to do so in practice with the data available to us. Rather than simply looking at their ability to prevent runs on batted balls, we have to divide up catcher defense into several parts to grasp it. While fielding batted balls and throwing to bases is part of what catchers do, most of their influence is more subtle. While statistics such as UZR and DRS are far from perfect, they offer significant insight into the quality of defenders at seven or eight positions. Evaluating catcher defense is extremely difficult do to the nuances of the position.

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