Introducing Statistics: Catching
Prompted by yesterday’s post, I would like to spend some time about catcher-specific statistics. Given that three of weakest hitters in the postseason are catchers, it seems worth asking if I am approaching catchers, as a class, in the wrong way. Let me raise a series of questions and pose some incredibly tentative answers to the problem of catching.
Catchers’ hitting is measured in the same way as all other hitters, but it has two confounding factors. Catchers, as a group, have less plate appearances and play less games than other positions. When they do play, they are more likely to play through injuries, given the physical demands of the position. Because of this, Hall of Fame catchers always have career stats substantially lower than the best at other positions. Even great hitting catchers, like Mike Piazza, has an OPS+ of 142. In comparison, Frank Robinson’s is 154 and Mel Ott‘s 155. Robinson and Ott, though great players, are at best the third and fourth best hitters ever at their position. Catching downgrades production.
The defense of catchers is nothing like that of other position players. The website Fangraphs is the best acknowledgment of this; they do not have any catcher stats in their advanced defensive categories. Others have attempted to fill in where stats like Ultimate Zone Rating leave off. A recent post attempts to put some statistical effort into catchers’ defense. The author rates catchers in three areas, errors, wild pitches/passed balls, and stolen bases/caught stealing.
Stolen bases are one of the trickiest areas to analyze. If one simply looks at caught stealing, one misses the impact a catcher has on the decision to attempt a steal. As Bill James pointed out in The New Historical Baseball Abstract, runners did not run on Johnny Bench after his rookie season. From that point on, his caught stealing rates were below average, because the only people running on him were extremely fast, had a great jump, were desperate, or all three. James proposes using catchers’ independent putouts (i.e. total putouts – strikeouts) as a better measure. While this gets at the range of catchers, it is heavily park-dependent. It is easier to get lots of putouts in the cavernous foul territory of the Oakland Colosseum than anywhere else.
The defense of catchers is still something of a statistical black box. Some attempts have been made to bring some light to the darkness. The Driveline Mechanics post is one of the best attempts, as it tries to assimilate a variety of data and comes up with rankings that make some intuitive sense (i.e. that Gerald Laird is a good catcher and Mike Napoli atrocious.) These results help explain why Napoli is not in the lineup everyday and why the weak-hitting Laird is still employed. This area is still murky enough, though, that there is plenty of room for constructive suggestions about how to measure catching better.