"Notice the drop in Sanchez’s fastball velocity, coupled with the increase in his change-up velocity. In 2010, the difference in speed between his fastball and his change-up was 8.7 mph. This season the difference shrunk to 5.9 mph. At a slower speed, his fastball was easier to hit, and at a higher speed, his change-up was easier to detect, resulting in fewer swing-throughs on both pitches. That’s corroborated by the drop in Sanchez’s O-swing numbers over the last three seasons.
What accounts for the changes in Sanchez’s velocity since 2010? Perhaps it’s the left bicep tendinitis that’s bothered him since last season. Or changes in his mechanics. Or maybe it’s the fact that Sanchez will turn 30 years old in November."