Over the first half of this season, it appears as though Yadi’s defense is rebounding from a relatively poor 2008 season. His CS% is up, his WP+PB/G is down, and he has just 2 errors on the season. A catcher’s defensive value is very difficult to capture b/c, unlike every other position’s, range plays a very small part – despite Yadi’s terrific play on Mark Teixeira’s squibber in the ASG last night. This is why there’s no UZR for catchers and why it’s not reported over at fangraphs.
In order to compare Yadi’s defensive value so far to the other NL catchers, I used the stolen base and caught stealing data from baseball-reference and the other data was gathered from THT. The run values for the various events were gathered from everybody’s favorite discussion piece -- The Book. A passed ball is worth 0.269 runs, a wild pitch is worth 0.266 runs, a stolen base is worth 0.175 runs, and a caught stealing is worth minus 0.467 runs. In the table below, BR runs represents the number of runs that a catcher has cost his team by being unable to throw base runners out. A negative number means that he’s prevented more runs than he’s cost his team by throwing runners out. Miss runs represents the number of runs that the catcher has cost his team through wild pitches and passed balls. Finally, what hasn’t been accounted for is the deterrent effect of a catcher’s reputation. How many runs does Yadi’s reputation save by preventing runners from even attempting to steal? I estimated this determining each player’s expected stolen base attempts against – simply the league average SBA (0.80 per game) times the catcher’s number of games. Subtract the actual SBA from the expected SBA and multiply that times the value of the stolen base (0.175 runs – since runners are forgoing the opportunity to add .175 runs to their total b/c of the catcher’s rep) and that gives us Rep Runs. Add the BR runs, the Miss runs and the Rep runs together to get the Total Runs against. TR/150 puts the Total Runs against on a 150 game scale. RAA is then the number of runs above (if positive) or below (if negative) average for each catcher. Obviously, low scores are better for TR/150 and high scores are better for RAA.
|Inn||SB||CS||WP+PB||BR runs||Miss runs||Rep runs||Total runs||R/150||RAA|
Catchers’ defense, of course, isn’t as simple as I’ve made it appear. Pitchers have an impact on the number of wild pitches thrown and stolen bases attempted. The score, the opponent, and the ballpark will also affect the number of stolen bases attempted. But, if you’re looking for a strong defensive catcher, you want one who can throw out base runners and block balls in the dirt. IMO, this measurement captures that as well as I’m capable of capturing it though I’m certainly willing to listen to your feedback.
It shouldn’t go unnoticed that Yadi comes out on top – largely b/c of his reputation and his ability to throw out base runners. He’s actually not done particularly in preventing wild pitches or passed balls. Carlos Ruiz of the Phillies has had a tremendous first half defensively and is only hurt by the fact that he hasn’t yet developed the reputation that people like Yadi and Pudge have. In any case, Yadi appears to be having a career season. My only concern is that his workload will catch up to him and he’ll wear down over the season’s second half. Still, Yadi at 75% has got to be better than Jason LaRue at 100% so I suppose we’ll have to chance that, won’t we?
Edit: I've made a substantial change to the Rep runs column. After rethinking it some, it seems to me that the value of a catcher's reputation is that the runner gives up the opportunity to steal the base. The value of that steal to the runner is equal to the value of the SB (0.175 runs) times the likelihood of success (1-CS%). In the original spreadsheet, I only used the 0.175 runs. Making this change alters the results some and drops Yadi below Carlos Ruiz by about a run and a half. Still, I think this is the correct methodology. It puts Yadi on about a 6 run prevented pace based on reputation and a half a win sounds a little more accurate than the full win pace I had initially.