Umpire Bob Davidson argues with Cole Hamels #35 of the Philadelphia Phillies as Placido Polanco #27 holds him back during the fifth inning of a baseball game against the San Diego Padres at Petco Park on April 20, 2012 in San Diego, California. Hamels was charged with a balk. (Photo by Denis Poroy/Getty Images)

By The Numbers: Understanding The Balk

The balk is one of the most confusing, poorly understood, and obscure aspects in baseball.