Midway through September, Mike Petriello of MLB.com introduced a newly available StatCast metric: Outs Above Average (OAA). This is the latest entry in a line of attempts to quantify outfielder effectiveness, which began at route efficiency and graduated to catch probability this season.
Outs Above Average uses the catch probabilities of individual plays to award outfielders with a point value based on the difficulty of the catch. To illustrate, here’s a running catch made by Ender Inciarte of the Atlanta Braves:
With a 9% catch probability, Inciarte’s catch adds 0.