Depending on the study, it is estimated that 8 - 13% of the world's population is left-handed. Now before all you righties click off, there is something for you in this post that relates to Major League Baseball.
Other than playing first base, most infield positions are clearly off-limits to southpaws because of the awkwardness for left-handed players to make standard throws from them. Shortstop or second base, no way. There's not a great case for lefties playing third base either despite the advantage of having the gloved-hand closer to the line.
But between the large number of switch-hitters and right-handed catchers who bat left-handed, I think the near-total lack of left-handed catchers at the professional level is more related to baseball tradition and prejudices than anything else.
I have not seen any statistics that suggest that right-handed catchers throw out any more or fewer runners attempting to steal depending on whether the hitter is batting left or right-handed. [If you know of any such stats, please pass them along]
In my opinion, left-handed catchers have better throwing angles to first or third base on balls hit in front of the plate. Throwing to first base, there is no need for them to throw around runners who are supposed to run outside the line. [Full disclosure: - observe the picture of me catching in an amateur game in the right column of this blog.]
Perhaps the best argument for not having left-handed catchers is that it is slightly more awkward for them to make plays at the plate because of the need to move the mitt across their bodies to get runners who again run mostly outside of the line. But the difference in time is small and how many close plays at the plate are there in an average game?
Where I think baseball's unjustified discrimination against left-handers is more apparent and costly is on the mound. Sure there are tons of southpaw pitchers in the game. And it often seems that clubs will give any lefty with a pulse the chance to win a relief job, even if they have long histories of being ineffective.
More than anything else, I think left-handed pitchers get a raw deal from umpires. Dusty Baker, summarized the difference between left- and right-handed pitchers when he said: "Have you ever played catch with a lefty? They just can't throw the ball straight."
He's right. Who knows why, but generally right-handers tend to throw the ball more over the top while lefties tend to throw more across their bodies. Since human beings are not symmetrical inside, perhaps it just has something to do with how people throw.
Because their balls tend to have more sideways movement, you would think pitches thrown by left-handed pitchers would have a greater chance of crossing the plate at some point, compared with righties, who throw straighter.
In my experience charting tens of thousands of pitches for both left- and right-handed Major League pitchers, the opposite is true. Lefties get fewer called strikes on borderline pitches, particularly inside ones.
I think there is a pretty simple explanation for this. Because their pitches come in toward right-handed batters, some umpires are susceptible to being taken in by exaggerated reactions of hitters who raise their arms or fall away on inside pitches, ostensibly to avoid being hit.
For several seasons, I worked with a left-handed pitcher named Brian Anderson who pitched in the big leagues for 13 seasons, and won a World Series ring with the Arizona Diamondbacks in 2001.
I can't tell you how many times when charting his video that I saw Brian make good inside pitches with a lot of movement that caught part of the plate but were not called strikes.
Like many finesse pitchers who work with a small margin of error, Brian would sometimes gave up a hit on subsequent pitches after not getting a called third strike he deserved. And you know what can occur when innings are extended unnecessarily. I think this happens a lot to left-handed pitchers, who must be able to work the inside of the plate in order to be effective.
But what do you think? Have you observed anything like this? Let's talk baseball!