Why is it shaped the way it is?
According to this article:
- The rounded edge is to facilitate successfully catching throws to first that wind up in the dirt, by funneling the ball into the glove.
- Its width is to give the biggest possible target/catching area for throws to first.
- Its deep web makes it less likely for balls to pop back out when being caught; since it’s relatively uncommon for a first baseman to have to immediately throw a ball after catching it, he can get away with a deeper web than other infielders.
Note that the rules of baseball -specifically rules 3.05 and 3.06 - do not allow fielders at other positions to use that type of glove (generally called a “trapper.”) It’s reserved for the first baseman.
I am not sure when in baseball history they allowed first basemen to wear different gloves. It’s certainly a really, really old rule.
Not as old as I thought. According to this website it was done in a set of 1950 rule changes.