In my opinion, slight changes in mechanics and movement can always tell the story of a player’s ups and downs throughout the course of a season. There is a reason why players go through ebbs and flows. Movement translates into success or failure. For pitchers, the fine details behind the way and direction in which they release the ball are enough to tell the difference between balls and strikes.
Proprioception (the ability to feel one’s body in space) is a significant indicator of whether a pitch can make adjustments on the fly or not. Sometimes, your body restricts your ability to make those adjustments, and sometimes, it’s their brain (it also can be both).