BAA (Batting Average Against)
PitchingOpponents' batting average against the pitcher: hits allowed divided by at-bats against. Lower is better; league average is around .245.
Batting average against is batting average from the pitcher’s side: how often the hitters facing him get a hit. Like batting average, it ignores walks entirely.
It also inherits every problem BABIP describes. A pitcher in front of a strong infield defense will post a lower BAA than an identical pitcher in front of a weak one, and the gap can be 20 points or more without either pitcher throwing differently.
Use BAA as a description of what happened, not as an evaluation of the arm. Pitching NUT, built on strikeouts, walks, and home runs, is the version with the fielders taken out.
What is a good BAA?
BAA is not used in NUT. It moves with the defense behind the pitcher, which is exactly what FIP-based pitching NUT is built to remove.
How NUT Score works →