It might not be too surprising that the Cardinals have the best record in baseball. But even the biggest baseball nut could be forgiven for not recognizing the guys taking the mound for St. Louis. On Tuesday against Arizona, rookie Michael Wacha, one of five St. Louis pitchers to debut this season, makes the start. Wacha is one of nine rookie pitchers to have made an appearance on the team's active roster so far this year.

For comparison, we took a look at teams in recent history that have used the most rookie pitchers. Not...