Ronald Acuña Jr was actually really...unlucky last year?

This one's hard to square when you look at all of the bold on Ronald's Baseball Reference page for last season: he led all of MLB in hits (217), runs (149), on-base percentage (.416), stolen bases (73), and total bases (383), while leading the National League in plate appearances (735) and at-bats (643), OPS (1.012), and OPS+ (168).

But under the hood, the stats show that it could have been even better.

(Warning, advanced statistics ahead.)

Weighted On-Base Percentage is your standard on-base percentage, adjusted to account for the additional value of an extra-base hit over a single. Ronald's was the 2nd best wOBA in baseball last season at .428, behind only fellow MVP Shohei Ohtani.

But when Statcast figures in the quality of the batted ball events for Ronald (accounting for exit velocity, launch angle, etc), Acuña's Expected wOBA was actually .460, a 32-point difference. That's the second-largest negative gap amongst hitters with 500 plate appearances, behind only Toronto's Vlad Guerrero Jr and his .035.

It's a similar story for Batting Average, with Ronald's Expected BA being .357 against an actual .337.

Most of this is attributed to some bad luck, and as we discussed on the podcast after Atlanta lost to Philly in the NLDS, luck can manifest in things like a significant underperformance in a small sample size (a distinction that was lost on all the Philly fans in the comments.)

Petriello notes that Ronald had thirty-one barrels - defined as a combination of a batted ball at 95 miles per hour exit velo or higher at the proper angle that's conducive to hitting a home run - that went for outs. 31 outs on barrels isn't just tops in baseball in 2023, it was actually the highest single-season figure in the Statcast Era (since 2015).

And Petriello goes on to add that Ronald also had nine batted balls of 390 feet or farther that were either outs or singles, when just hitting a batted ball that distance results in an extra base hit 85% of the time. 

Ronald's defense can absolutely improve

There's differing opinions on Ronald's defense depending on who you ask - Braves fans think he's as clutch and reliable as he's ever been, while outside observers think Ronald's not very good at all. 

The truth is actually in the middle. While it's obvious Ronald's arm is a weapon - we frequently saw runners hold up at second rather than try to stretch to third on a base hit to right field - the advanced stats weren't so kind. 

The issue comes down to routine plays - Ronald's graded out pretty poorly on the first parts of a defensive play for an outfielder, the read and the reaction. Statcast has him at negative values for both the "reaction", or the direction of the first step, as well as the "burst", how much ground he covers in the initial few movements after a ball is hit. 

Petriello theorizes that some of it is Ronald protecting the surgically repaired right knee, and it could be either deliberate or subconscious on Acuña's part, but just improving to average from a defensive range perspective would have brought Ronald's 2023 WAR from 8.3 to 8.9.  

Ronald wasn't actually the most efficient basestealer

Here's the other area, along with the defensive numbers, where the "Mookie Betts for MVP" stans attacked Ronald last season. 

Acuña was only 84% successful in stolen bases last season, with the other league leaders coming in the 90s, something that resulted in Ronald being oputside the top five in advanced baserunning metrics. And, Petriello notes, it's largely focused on two areas: Getting thrown out at second base and getting picked off. 

Ronald was thrown out twelve times trying to steal second, while he was picked off of first base five times and picked off twice at second. 

And as we've discussed before, there's no need to be ultra-aggressive on the basepaths with this Atlanta offense behind him, as there's a strong likelihood one of the trio of Ozzie Albies, Austin Riley, or Matt Olson will be able to drive Ronald in whether or not he's on first, second, or third base to open any given inning. 

Wild to think that Ronald can get even better, right?

I'm struggling with proper expectations for Ronald Acuña Jr in 2024, because he was so good last season but at the same time, there's some obvious areas that he can make small adjustments to be even better next season. 

Either way, it's clear that he's one of the most dynamic players in baseball and the Braves are probably the most dangerous offense in MLB with him at the top of the lineup. 

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