Atlanta Braves: Why Ronald Acuna Jr. Ranks in Bottom 5% in Outs Above Average (OAA)

Atlanta Braves superstar Ronald Acuna Jr. is on his way to an MVP this year. I don't think Mookie Betts stands a chance. However, one of the most polarizing topics is whether or not Acuna is good at defense.

Overall, he is around league average in terms of defensive runs saved compared to right fielders. He makes great plays at the wall and his cannon of a right arm holds runners at bay. Should they run, they will pay.

So, why do some say he's not good at defense?

Because he lacks range. I know, it's a weird thing to say for a guy who leads the league in stolen bases. Speed doesn't always equate to range in the outfield. Yes, you need speed but you also have to read the ball well and take excellent routes. That is how Major League Baseball players maximize their range in the outfield. Ronald Acuna Jr. is bad at that.

Now, I have written about Acuna's defense in the past. I wrote a piece called Is Ronald Acuna Jr. Bad At Defense? Does it Matter? Think of this as an updated companion piece. My sole inspiration for writing the first one was to learn about why metrics like OAA looked so unfavorably upon Ronnie.

Acuna pulled up on a flyball in Sunday's loss to the Dodgers and it inspired me to check in on his defensive metrics. There is a link to the video of him whiffing on a routine flyball from Jason Heyward later in the article.

So, here is an update on Acuna's Outs Above Average (OAA) and examples (with links to videos) of Acuna missing on high probability catches.

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.

Ronald Acuna Jr. Defense - Video Evidence

Let me start by directing you to a really cool page. The fielding section of Ronald Acuna Jr.'s Baseball Savant player page. If you scroll down, you can see a chart showing the catch probability for Acuna's plays this season.

Now, I would like to direct your eyeballs to video evidence of plays Acuna didn't make that most major-league outfielders would have.

Exhibit A - Acuna Can't Make the Play on a High Fly with 99% Catch Probability

Exhibit A - The catch probability on (the video is in the "Exhibit A" link) Exhibit A is 99%. So watch the video and just know that based on the distance he needed to travel and the time the ball was in the air, 99% of major-league outfielders would have made this play.

You can see Acuna makes a bad read backward, then he freezes for an odd amount of time and then goes on a sprint toward the ball. Even the announcers were shocked. This is a good example because a lot of camera shots don't cut to the outfielder quickly enough to show the initial read.

Exhibit B - Acuna Pulls up on Flyball with 99% Catch Probability

Exhibit B - Here Acuna pulls up on a ball that most players would catch. I included this one because we have seen this a lot from Acuna this year. They aren't always on 95% catch probabilities, but this one is.

Exhibit C - Acuna Gives Jason Heyward a Hit by Pulling up on Flyball with 95% Catch Probability.

Exhibit C - Here is the ball he pulled up on against the Dodgers. Jason Heyward hit a "routine flyball" as the announcer said. Acuna pulled up and let it fall. This is a ball most major-league outfielders are going to catch. When I saw Acuna stop short on this ball on Sunday, it brought back memories of the research I had done. That ball should have been caught, especially with Acuna's speed.