… Trackman measures not just the speed of the pitch, but also the key variable: the distance between the pitcher’s release point and the plate. With those measurements, Trackman defines not only the time component of a fastball — “flight time,” if you will — but also defines in irrefutable data why scouts might describe a pitcher as “sneaky fast” or throwing a ball with “hop.”
… Imagine if Robertson moves the pitching rubber 14 inches closer to home plate every time he pitches. That’s the kind of advantage he gains over the average pitcher by releasing his fastball with so much extension. The radar gun (and Trackman) clocks Robertson’s fastball at an average of 93 mph. But because Robertson shortens the distance between his release point and home plate, his “effective velocity” is 95 mph. It looks like 93 but gets on a hitter like 95 — thus the illusion of “hop.”When it comes to “stealing” distance — and distance equals time for a pitcher – here are the top 10 pitchers from one AL park last year, ranked by fastball extension in feet and inches:
| Pitcher, Team | Extension | MPH | FT* | Effective MPH |
| … | ||||
| Sergio Santos, White Sox | 6-10 | 96 | .386 | 98 |
| … | ||||
| Gavin Floyd, White Sox | 6-8 | 92 | .407 | 93 |
| … | ||||
| Average MLB | 5-10 | 92 | .416 | 92 |
