Just FYI. One of the answers is wrong. Chapman's fastest pitch was 105.1 mph on 9/24/2010. The 106 stadium reading on 4/18/11 (the TV reading was 105 mph) was actually 'only' 102.4 in Pitch F/X. Further, while Chapman is the fastest pitcher in the Pitch F/X era (2006+), he is only the 3rd fastest pitcher ever.