World Baseball Classic roster: Which St. Louis Cardinals farmhand will be pitching for Spain?

Thursday's provisional announcements of the 2013 World Baseball Classic rosters offered a few surprises—Mitchell Boggs will play for Team USA, and Jaime Garcia won't play for Team Mexico—but the biggest surprise, or at least the small surprise I was least prepared for, was that the St. Louis Cardinals would be sending one of their own to... Team Spain. It's none other than Richard Castillo, one-time sleeper prospect and a classic example of how misleading age relative to league can be for pitchers.

Castillo reached the full-season minor leagues at just 18 years old, back in 2008, and put together some excellent starts in high-A Palm Beach. But his stuff (not overwhelming) and his size (not six-feet-tall) meant scouts were skeptical, and it turned out they were right to be; he's spent most of the next four years in the same place, trying to get out of the Florida State League.

In 2012, still just 22, he finally did, putting together a 3.76 ERA over 110 innings at AA Springfield. And with Team Spain not exactly crawling with homegrown talent after three World Baseball Classics, Castillo—a native of Venezuela—is more than qualified, by blood and results, to take the mound. (Here's the full roster.)

When the WBC's Pool C convenes on March 8, Richard Castillo and company will take on Puerto Rico—featuring two bigger-name Cardinals stars—the favored Dominican Republic, and Venezuela itself. They're the heavy underdogs in one of the classic's strongest pools, but they had to impress in the qualifiers just to get this far.