The New York Times recently published a piece which pondered the extreme rarity of left handed catchers in Major League Baseball. In the course of the piece, they also take a look at the dearth of left handed third basemen, shortstops, and second basemen. Being an issue I've actually given a lot of thought to, I wanted to share a few thoughts on the matter.
As sought after as left handed pitchers, first basemen, and hitters are, baseball is not a terribly left hand friendly game, especially in the infield. It has been said that the measurements of a baseball diamond are as close to perfection as possible, with the number of bang-bang plays, particularly at first, being held up as proof. It is those bang-bang plays that make the infield an unfriendly place for lefties. Infielders, particularly on the left side of the infield, must get their throws off as quickly as possible. Good throwing mechanics dictate that the best throws will be made when you lead in some fashion with the shoulder of your glove hand. For right handed infielders, that is the left shoulder, which is naturally positioned in the general direction of first base. Left handers, meanwhile, must turn their body more to make good, strong throws. It doesn't seem like much, but over the course of 162 games, that turn might make the difference between a dozen, maybe two dozen runners being safe or out. That may not seem like much, but if it changes the outcomes of three games, it can make all the difference in the world.
Catchers are more difficult to explain. The entire game transpires before a catcher and as such, the angles of the game are not as detrimental. It seems clear that there could be successful left handed catchers, but why aren't there any? The scarcity of the left handed arm probably has a lot to with it. A good catcher is probably going to have one of the top two arms outside of the pitcher in your lineup. As valuable as left handed pitching is, if given the choice between using a power left handed arm on the mound or behind the plate, you are almost always going to choose the mound.
Now, what about that incredible left handed offensive talent with an average arm but solid defense? That player is probably going to end up at first base for a couple of reasons. Catcher is a brutal position. Most moms figure that out in Little League. Coaches at all levels will usually want to preserve the offensive production of a big time hitter by moving him out from behind the plate. Second, that hypothetical offensive talent with an average arm is probably going to be bested by a stronger armed right hander who can throw out base runners by high school. The safe place to put that player to accentuate his positives is first base, a position where it is advantageous to have a lefty and where the lessor arm strength can be hidden.
There are a lot of myths about left handed catchers and the Times looks at a number of them but never really gets to the nut of the problem. The fact is that the opportunity cost of playing a scarce, talented left handed thrower behind the plate is just too high. Whatever their mix of skills, there are better positions for them on the field. That is why you don't see left handed catchers in professional baseball.