In recent years, many new methods to evaluate pitchers have emerged.
With stats like FIP, xFIP, and SIERA, we now have the ability to more accurately measure a pitcher’s true skill, independent of the defense behind him that can make him look better or worse.
Tracking systems like PITCHf/x identify every pitch thrown, along with the movement and speed on each.
Statcast has given us even more information, measuring things such as perceived velocity on pitches, along with exit velocity and launch angles on each batted ball.
These systems are even able to track the revolutions per minute of each and every pitch thrown in the majors.