We’ve all seen David Robertson pitch, maybe even 100 or more times by now (138 career appearances). He’s a little guy (listed at 5-foot-11) and his fastball sits in the low-90’s (averaged 91.6 mph in his career), but why does it look like it’s moving faster? The better question is: why do hitter react like it’s faster? The answer, as Tom Verducci explains, is extension.
A Danish company called Trackman, which already has a death grip on golf data capture and analysis, has installed equipment in a number of MLB (and minor league) parks that record a 3-D Doppler radar measurement of pitch’ flight. It’s not necessarily how fast the pitch moves, but how much time batters have to react to it. Robertson releases the ball seven feet in front of the pitching rubber because of his long stride, compared to the MLB average of 5-feet-10. He’s effectively stealing 14 inches from the hitter, and that makes his fastball look more 95 than 91-92. That seven-foot extension is the longest by any pitcher recorded last season.
The Trackman system also records pitch rotation, and the faster the pitch the rotates, the more it moves and the hard it is for batters to pick up. At 2,690 rotations per minute, Ivan Nova‘s curveball had the eighth greatest measured rotation last year. Justin Verlander’s curveball was tops, Al Aceves‘ was fourth. Verducci’s post also shows the impact that greater extensions and pitch rotations have; the end result is more swings-and-misses. Make sure you check it out, it gets RAB’s highest level of recommendation.