Torn ACL Ends Ronald Acuña Jr.’s 2021

The Atlanta Braves had justifiably high hopes coming into the 2021 season. Despite the early loss of Rookie of the Year runner-up Mike Soroka, the 2020 Braves won their third straight division title. If the postseason had been four innings shorter for Atlanta, they would have made their first World Series of the 21st century, 21 years after getting swept by the Yankees. Almost all of the key players returning fueled preseason optimism, but rather than tangling with the NL’s best teams, the Braves are in a grueling brawl to finish above the .500 line. The disappointment was already in full force before the team took their biggest hit yet: the sight of outfielder Ronald Acuña Jr. being carted off the field after an attempt to make a leaping catch.

As with any injury, the initial beleaguered hope was that Acuña would rub some sweat or dirt or spit onto the painful area, walk it off, and be ready to jump back into the lineup. Everyone dodged a bullet — well, maybe not opposing pitchers — earlier this season when Acuña injured his abdomen after diving on a pickoff play but quickly returned to the lineup. Before the night was out, however, an MRI confirmed that this was a serious injury, a torn right ACL that will end Acuña’s season.

Acuña already looked like a special player before the season started, but he somehow looked even better this year, still just his age-23 season. Hitting .283/.394/.596 with 24 home runs, a 161 wRC+, and 4.0 WAR, he had already crammed a whole season’s worth of awesome into a half-season bag. The ZiPS projections had Acuña finishing with 44 homers and 7.2 WAR, the latter number one the best for all position players, vanquishing his competition in the Battle of the Legacies (Vladimir Guerrero Jr., Fernando Tatis Jr.), though falling to best Shohei Ohtani when pitching contributions are included.

The 2021 heroics didn’t look like a one-shot deal. As I wrote before the 2020 season blew up, Acuña was projected to fight with Juan Soto in the coming years for the privilege of topping Mike Trout as baseball’s best player.

The power and speed in Acuña’s secret blend of 11 tools and skills are quite well-known at this point, but one ingredient may actually be underrated: his plate discipline. Like his rival Soto, Acuña defies the stereotype of a young, blazing star who is also perhaps a tad too aggressive at the plate at times. In terms of plate discipline, he’s right up there with players who get far more acclaim for being picky:

Swing Differential Leaders, 2021
Name Out-of-Zone Swing% Zone Swing% Difference
Kyle Tucker 30.2% 82.8% 52.6%
Freddie Freeman 29.0% 79.5% 50.5%
Chris Taylor 24.2% 73.3% 49.1%
Jed Lowrie 22.6% 71.6% 49.0%
Vladimir Guerrero Jr. 25.1% 74.1% 49.0%
Dansby Swanson 27.4% 76.0% 48.6%
Brandon Crawford 31.1% 79.5% 48.4%
Ozzie Albies 37.1% 84.6% 47.5%
Juan Soto 16.0% 63.4% 47.4%
Bryan Reynolds 29.0% 76.3% 47.3%
Fernando Tatis Jr. 34.4% 81.6% 47.2%
Andrew McCutchen 21.1% 67.2% 46.1%
Kris Bryant 29.9% 76.0% 46.1%
Matt Olson 27.2% 73.3% 46.1%
Ronald Acuña Jr. 23.9% 69.7% 45.8%
Alec Bohm 30.5% 76.2% 45.7%
Gleyber Torres 27.6% 72.7% 45.1%
Joey Gallo 23.2% 68.1% 44.9%
Robbie Grossman 19.2% 63.7% 44.5%
Kyle Schwarber 24.1% 68.5% 44.4%

I wouldn’t classify any of this as good news, but the recovery rate of baseball players who undergo ACL reconstruction is quite good, and Acuña is younger than the average player. One study found a mild, but real, negative effect on stats for returning players. But I’m not so worried about that; I’ve examined ACL data (for a non-identical group of players) in the past, and while I found a lower batting average than well, I didn’t find a similar effect when measuring future performances relative to the projections made before the injury. In other words, a lot of that drop-off was due to aging and regression toward the mean.

ZiPS Projection – Ronald Acuña Jr.
Year BA OBP SLG AB R H 2B 3B HR RBI BB SO SB OPS+ DR WAR
2022 .275 .384 .562 509 117 140 27 1 39 100 80 160 29 144 5 5.6
2023 .275 .387 .576 498 117 137 28 1 40 101 82 161 27 148 4 5.7
2024 .270 .386 .572 493 117 133 27 1 40 100 85 164 29 147 4 5.6
2025 .267 .388 .572 486 117 130 26 1 40 99 87 165 26 148 4 5.5
2026 .266 .390 .567 473 114 126 26 1 38 95 87 161 26 147 3 5.3
2027 .265 .390 .559 460 110 122 25 1 36 91 85 151 25 145 3 5.1

Naturally, there’s a playing time risk simply because we’d be lying if we said there was no uncertainty. But ZiPS projects Acuña to return to just about the same type of player he was before the injury. For his career, ZiPS drops Acuña’s final WAR total from 84 wins to 76 wins, still Cooperstown territory.

While Acuña’s focus will naturally be on his recovery, the Braves have to deal with the fact that they’ve lost their best player for the rest of the season. And the truth is that Atlanta was already in trouble. Being below .500 in July is different than in April, and the calendar is just as dangerous an opponent as a Mets team getting some of their key contributors back from injury. Imagine a fairy tale in which while Acuña slept Monday night and three elves snuck into his house and cobbled together his ACL. Let’s check out the projected standings with the help of those magical orthopedic surgeons:

ZiPS Projected Standings – NL East (Fairy Tale)
Team W L GB Pct Div% WC% Playoff% WS Win% #1 Pick Avg Draft Pos
New York Mets 88 74 .543 64.9% 2.2% 67.1% 5.9% 0.0% 21.0
Philadelphia Phillies 84 78 4 .519 18.5% 2.7% 21.1% 1.5% 0.0% 16.8
Atlanta Braves 83 79 5 .512 14.5% 2.3% 16.9% 1.2% 0.0% 16.2
Washington Nationals 79 83 9 .488 2.1% 0.3% 2.4% 0.2% 0.0% 12.1
Miami Marlins 71 91 17 .438 0.0% 0.0% 0.0% 0.0% 0.0% 7.3

With Acuña suddenly back in the lineup and at 100%, the Braves still only have about a one-in-six chance of making the playoffs, usually by besting the Mets in the division. But we’re not in a fairy tale. Well, maybe a German fairy tale. Regardless, the standings generated from more reality-based projections paint a bleaker picture:

ZiPS Projected Standings – NL East
Team W L GB Pct Div% WC% Playoff% WS Win% #1 Pick Avg Draft Pos
New York Mets 89 73 .549 71.6% 1.7% 73.3% 6.4% 0.0% 21.4
Philadelphia Phillies 84 78 5 .519 21.3% 3.0% 24.3% 1.8% 0.0% 17.2
Atlanta Braves 80 82 9 .494 4.5% 0.7% 5.2% 0.3% 0.0% 13.6
Washington Nationals 79 83 10 .488 2.6% 0.4% 3.0% 0.2% 0.0% 12.5
Miami Marlins 72 90 17 .444 0.0% 0.0% 0.0% 0.0% 0.0% 7.5

The Braves aren’t dead, but some 70% of their already shrinking number of playoff scenarios dissipate into the mists. They’ve gone from trying to catch a flush on the river to trying to complete a straight flush. General manager/president of baseball operations Alex Anthopoulos will certainly feel pressure to make a move to replace Acuña, but the truth is that there really isn’t such a move out there. The Braves already needed at least one additional starting pitcher. They still haven’t found an actual replacement for Marcell Ozuna, who is currently on the Injured List and faces domestic violence charges and a possible MLB suspension following a May incident at his home. In our depth chart rankings, Atlanta now projects to have the second-worst outfield in the majors, ahead of only the Tigers:

FanGraphs Depth Chart Projections – Outfield
Team LF CF RF Total
Dodgers 1.0 2.5 2.7 6.2
Astros 1.5 1.2 1.7 4.4
Nationals 0.8 0.9 2.7 4.4
Twins 0.8 2.3 1.2 4.3
Padres 1.3 1.9 0.8 4.0
Yankees 0.6 0.8 2.5 3.9
Blue Jays 0.9 1.9 1.0 3.8
Brewers 1.9 1.1 0.7 3.7
Rays 1.3 1.2 1.2 3.7
Mets 0.9 1.3 1.5 3.7
Angels 0.7 2.8 0.1 3.6
Cubs 1.1 1.1 1.2 3.4
Phillies 0.7 0.7 2.0 3.4
Reds 1.4 0.8 1.1 3.3
Athletics 1.1 1.7 0.5 3.3
Orioles 0.8 1.5 0.9 3.2
Cardinals 1.0 1.4 0.6 3.0
Red Sox 0.8 1.1 1.0 2.9
Giants 0.7 0.9 1.3 2.9
Marlins 0.4 1.6 0.9 2.9
Rangers 0.2 0.7 1.9 2.8
Diamondbacks 0.6 1.3 0.7 2.6
White Sox 1.0 0.9 0.4 2.3
Royals 0.8 0.8 0.6 2.2
Cleveland 0.8 0.8 0.5 2.1
Pirates 0.3 1.4 0.1 1.8
Mariners 0.2 0.7 0.9 1.8
Rockies 0.4 0.3 0.6 1.3
Braves 0.6 0.4 0.2 1.2
Tigers 0.6 0.3 0.3 1.2

I’d argue that the Braves have passed the tipping point where they ought to transition into retooling (but not rebuilding) mode for the rest of 2021. Focus on getting Freddie Freeman’s extension done, giving extended shots without the pressure of a pennant race to Cristian Pache and Drew Waters, and see what you can get in return for the services of Charlie Morton and/or Drew Smyly. Losing Ronald Acuña Jr. is just about the loudest the fates can shout that your season is over.





Dan Szymborski is a senior writer for FanGraphs and the developer of the ZiPS projection system. He was a writer for ESPN.com from 2010-2018, a regular guest on a number of radio shows and podcasts, and a voting BBWAA member. He also maintains a terrible Twitter account at @DSzymborski.

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kylerkelton
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kylerkelton

As a Braves fan I 100% agree with your last paragraph. This season has been such a bummer.