How did Riley improve?
At the start of the year, it looked like he hadn't. By the end of April, Riley had already accumulated -4 OAA. However, once May started, Riley's defense turned around.
So, what's changed?
One huge difference is his positioning. In 2022, he was one of the closest-positioned 3B in baseball, starting 114 feet from home. Only five players who saw more than 1000 PAs on the field at 3B were closer.
This year, he's starting 121 feet back. He's now the 18th farthest away from home when a pitch is thrown on average.
He's also shifted far more to the left side of the infield but so has every 3B. This is likely a result of the shift ban. Still, in terms of positioning, he's gone from being, on average, positioned far closer to SS in 2022, to being placed closer to the 3B bag in 2023, at least compared to the average 3B.
So, has this actually helped or is this a case of correlation not equaling causation?
In 2022, Riley was worth -6 OAA at 3B. While he was fine going to 3B, he struggled going towards 1B, worth -3 OAA, or going in on balls, being worth -4 OAA.
In 2023, Riley improved greatly on balls going in, being worth 0 OAA. He's improved slightly on balls towards 1B, being worth -2. He's greatly improved on balls toward 3B, however.
It seems paradoxical that moving back would improve Riley's defense coming in on balls. Without being able to see which balls Riley failed to make plays on this season versus last (and being able to see out expectancy), I can't definitively say whether moving back has helped him.
However, moving back would make more sense when it comes to getting balls to his right and left. After all, he now has an extra few feet to field the ball.
Instead of letting a ball like this get past him, Riley is now giving himself an extra few milliseconds to field it.
Is Austin's defense for real?
If you've sworn by the eye-test, then Riley has always been a good defender. This year hasn't changed your mind.
If you haven't been a believer in Riley's defense and you don't watch every single second of every single game (most of us don't), it might be hard to buy into the idea that moving back a few feet was the missing piece all along.
Truthfully, there's likely a lot more that goes into Riley's improvements that I can't see because I don't have access to it (give me infield OAA videos, Baseball Savant). However, he's posted three straight months with above-average defense.
As we saw with Ozzie Albies earlier this year, defense from month to month can be fickle. But Riley certainly looks capable of continuing to play solid defense.