What is this? A Statcast metric designed to express the demonstrated skill of catchers at preventing wild pitches (WP) or passed balls (PB).
How this works: Every pitch is assigned a probability of being a passed ball or wild pitch based upon several inputs, most notably: pitch location, pitch speed, pitch movement, catcher location, and batter/pitcher handedness. Based on that knowledge, each pitch a catcher receives (or fails to) is credited or debited with the appropriate amount of difficulty. For example, if a catcher blocks a pitch that is a PB + WP 10% of the time, he will receive +0.10. If he blocks a pitch that is a PB + WP 90% of the time, he will receive +0.90.
How to read it: Blocks Above Average is the difference between actual PB + WP and estimated PB + WP based on opportunities seen. Blocks Above Average / game is a rate stat based on an average catcher receiving 40 blocking chances per game. Catcher Blocking Runs converts blocks to runs saved on a .25 runs/block basis