Barry Zito had the best curveball in the game, a pitch that batters couldn't hit and umpires struggled to judge. But somehow he lost it -- and what went wrong remains a mystery. The most educated guesses may come from Rick Peterson, Zito's pitching coach during his Cy Young season in 2002. With the help of slow motion video shot at the American Sports Medicine Institute in Birmingham, Ala., Peterson breaks down the mechanics and mind games behind Zito's curve.