Acuna Defense: How Outs Above Average (OAA) is Calculated
If you need a refresher on how OAA works, you can click here or accept my succinct run down in the next couple of sentences. Statcast measures the probability of a catch based on the distance the fielder needs to run to get to the ball and the hangtime of the ball. Based on those numbers, it calculates the probability of the average outfielder making the play. If a play is made by 99% of outfielders then there are two outcomes. One, the catch is made and the player receives the difference of the probability as a credit. 1-.99=.01.
You don't get a huge reward for making a play you are supposed to make in the big leagues. However, if you miss those routine plays, then you deserve a smack on the wrist. Missing the subtracts .99 from the player's score. That's detrimental to most defensive metrics. Players who lack range really stick out in OAA because when they miss a high-probability catch, they usually have a tough time making up for them with spectacular low-probability plays. In other words, it's all downhill from there.
Why is Acuna in the Bottom 5% in Outs Above Average!?
Thanks for listening. So, if a player like Kevin Kiermaier makes a mistake on a routine flyball, he's going to be fine because he gets tons of credit for making those highlight plays where he streaks through the outfield like a leather-seeking missile fired out of a fighter jet. On the other hand, if Marcell Ozuna misses a routine flyball... he's toast. He's not making that point up.
So, why is Acuna more like Ozuna rather than Kiermaier? Is something off here? Are we missing something? Go to the next slide to see what's actually going on. Videos are included on the next slide.