Kyle Hendricks was averaging 87.8 mph on his sinker in May and June, then he went on the injured list due to a shoulder impingement. That is well over one tick faster than the 86.4 mph he’s achieved over four post-injury starts. One noticeable change and potential explanation is that Hendricks’ release point is slightly different.
The Professor’s velocity usually correlates to release extension and vertical release point, but both mechanical marks have within his pre-injured range. However, his horizontal release point is about 2.5 inches further away from his body than it was before he got hurt.
Hendricks’ more recent horizontal release points mirror those from his late April outings (first figure below). And we clearly see a noticeable drop by pitch count right when he returned from the IL (second figure below).
It’s possible that this slower sinker is just a byproduct of regaining strength and feel, that Hendricks just needs more time to orient himself. But since returning from his injury, it’s clear that his horizontal release point has changed. This could be something to monitor moving forward.