Baseball players are dynamic. Not all in the way that, say, Javier Baez is dynamic, but in that their performance can change dramatically. Now, many year-to-year changes in performance can be chalked up to variance, or to a guy just having an off season. Most of the time, when a player sees a fluctuation in performance, it’s not actually because he suddenly became a completely different athlete.
Sometimes, though, players can change fundamentally, or at least perform in a way that’s clearly different from the past. In prior years, I’ve analyzed the Yankees that changed the most.