Aroldis Chapman
Parnell, in his short major league career, has already developed a reputation for being a flamethrower. His fastballs consistently touch the high-90s, sometimes eclipsing 100 MPH. On August 18, 2010, in a game against the Houston Astros, Parnell hit 102.5 MPH on the radar gun, the fastest pitch in the major leagues in 2010 up to that point. Cincinnati Reds rookie Aroldis Chapman set the new mark on August 31, 2010 at 103.9 MPH.