Bill James, from the "Hey Bill" section of his website:
...if you look at the history of the amateur draft, there has almost never been a second baseman drafted in the first round. I think in the entire 48-year history of the draft, 1200 or 1300 first-round draft picks, there are only a handful listed at the time of the draft as second basemen, whereas there are dozens and dozens listed at every other position.
I've never seen such an obvious case of blatant discrimination. [Chant] SECOND BASE, NOT SECOND CLASS! SECOND BASE, NOT SECOND CLASS!
The reason that is true is that the drafting organization gets to decide how to list the player, and everybody does the same thing we do: they don't ASSUME that a player can't play shortstop. Lots of players drafted in the first round were actually playing second base in college, but their teams still drafted them as shortstops, just on the theory that if they COULD play shortstop, that would be good.
Second basemen are really just a subspecies of shortstop. Ian Kinsler and Dustin Pedroia were both shortstops at Arizona State, but Kinsler was behind Pedroia on the depth chart, and ended up playing second and riding the bench. So he transferred to Missouri and starred there before being drafted by the Rangers as a shortstop.
Both Kinsler and Pedroia played more games at shortstop in the minors than second base. Well, Pedroia was about half and half. Essentially, every major league second baseman began life as a shortstop until his team was forced to play him at second base, either because he didn't have the arm for short, or, more often, because he was blocked by another player. Robinson Canó is a rare star second baseman who played more second than short in the minors. But when you've got a defensive dynamo manning shortstop for the big club, you don't change horses in midstream. No, you ride the horse until he dies, even though he can't go to his left anymore.