A few years ago, I introduced Stuff+ on these digital pages to help power the pitcher analysis in the series previews and elsewhere. It was an attempt to measure the raw stuff of a pitcher’s arsenal using the physical characteristics of their pitches. Back in 2019, this type of pitch evaluation was still a new frontier. Eno Sarris, Jeff Zimmerman, and a handful of others had dipped their toes into creating arsenal scores like this.
Fast forward two years and the amount of research into what makes individual pitches successful has grown exponentially. The biggest leap forward has been a much deeper understanding of how the spin imparted on a given pitch affects its flight path.