On catcher defense: Where's the tipping point?

For the second in our series of guest posts here at The Platoon Advantage, we are lucky to have Zach Sanders, who writes at too many places to count, including some of our favorites like Fangraphs.com, BaseballDailyDigest.com, and rotohardball.com.  Plus, Zach runs our fantasy football league.  In light of our discussion yesterday of Buster Posey's value, Zach's offering here seems very timely.

Even though we don’t have a perfect measure of what a catcher brings to the table defensively, that doesn’t mean that we don’t factor it in when evaluating a backstop. However, we don’t need to over exaggerate things just because the defensive player in question is a catcher.

Teams get all excited when they have a good defensive catcher, and many teams focus on finding a backstop who isn’t going to cost them games behind the plate. For that matter, they probably should, because finding a good offensive catcher is hard to do. But, if teams do find a catcher who can get it done in the batters box, they should probably play him, because offense and defense should be weighed equally.

Take Mike Napoli for example. Mike Napoli is a very good hitter, never having a wRC+ below 110. Yet, if not for injuries at multiple positions, who knows how often Napoli would have even seen the field? There must be a darn good reason, because Mike Scioscia’s a genius, right? Well, Scioscia didn’t like Napoli on the defensive end, and apparently couldn’t give less of a crap about what he does for the team offensively.

In 2009, Napoli was a 3-win player if we don’t factor in defense. Even if he was a very bad defensive player, say 10-runs (1 win) below average bad (which he was), he would still be a solid everyday player. Jeff Mathis, on the other hand, is a replacement level player player before a defensive adjustment. He would have to be the best defensive catcher in all of baseball to make playing him over Napoli worth your time. To drive the nail in even further, in the small sample that was 2010, Napoli was actually rated a better defensive catcher than Mathis.

Catchers are just like any other player. They play defense, and we place a value on it. That doesn’t mean we need to go crazy just because they touch the ball on every pitch. Yes, I am ignoring their ability to call games and handle pitching staffs, but we still don’t have much evidence that they have a big impact in that department. Even if we did, would a player like Mathis have a 10+ run advantage? I sincerely doubt it.

Big thanks to Matt Klaassen for 2009 catcher defense numbers.