Batting Average Against
BAAThe batting average opposing hitters post against a pitcher, calculated as hits allowed divided by at-bats faced.
Batting average against flips batting average around to the pitcher's side: hits allowed divided by at-bats faced. A pitcher with a .210 BAA is holding opponents to a .210 average.
It is a cleaner read on a pitcher than ERA in one specific way. ERA depends heavily on the defense behind the pitcher and on the sequencing of hits; BAA measures how often contact turned into hits, full stop.
It has the same blind spot as batting average: walks are invisible to it. A pitcher can post an excellent BAA and still be ineffective if they walk the ballpark, which is why it is read next to WHIP rather than alone.
What is BAA in baseball?
Batting average against: the batting average opposing hitters have against a particular pitcher. It is calculated as hits allowed divided by at-bats faced.
Is a low BAA good?
Yes. A lower batting average against means fewer of the opponent's at-bats are turning into hits. It is best read alongside WHIP, since BAA ignores walks entirely.
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