CHICAGO -- Ronald Acuña Jr. knew immediately.
Two steps before reaching first base, the Braves superstar felt something grab in his left hamstring. By the time he crossed the bag in the fourth inning Tuesday night, he was hobbling. Moments later, he was slamming his helmet in frustration and disappearing into the tunnel beneath the visitors' dugout at Rate Field.
For a player who has spent much of the past five years fighting through devastating injuries, it was a sight that stopped everyone in their tracks.
Acuña exited Atlanta's 6-5, 10-inning loss to the White Sox with left hamstring tightness and underwent an MRI on Wednesday that revealed a strained left hamstring, landing him back on the 10-day injured list. Acuña was previously sidelined by a Grade 1 left hamstring strain for 16 days earlier this season.
Infielder Rowdy Tellez was selected to the Major League roster and right-hander Jhancarlos Lara was designated for assignment in corresponding moves.
Atlanta wasted a pair of Matt Olson home runs, surrendered a four-run lead and watched White Sox rookie Braden Montgomery launch a walk-off homer in his Major League debut. But by the time players entered the clubhouse afterward, the outcome had become secondary.
The conversation centered around Acuña.
"I'm disappointed, man," Acuña said. "I don't know how many injuries you need to pass."
The sequence unfolded quickly.
With one out in the fourth inning, Acuña grounded a ball to third baseman Miguel Vargas. As he sprinted toward first base, he suddenly appeared uncomfortable. He continued running through the bag before hobbling several steps into foul territory in shallow right field.
The former National League MVP slowly limped his way back toward the dugout, visibly frustrated. He slammed his helmet before disappearing up the tunnel. When the Braves took the field for the bottom of the inning, Eli White had replaced him in right field.
Given Acuña's history, the reaction was immediate.
In July 2021, he sustained a season-ending tear of his right ACL. Three years later, another torn ACL -- this time in his left knee -- ended his 2024 season. Then came the hamstring strain on May 2 of this year, sustained while running out a ground ball against Colorado.
"We saw it not too long ago," Weiss said. "We needed him the last time. We've got our fingers crossed, hoping this one's not too bad."
Acuña believes it isn't.
Asked how Tuesday's discomfort compared to the injury that landed him on the injured list in May, he offered a noticeably more optimistic assessment than his manager.
"This one is easier," Acuña said. "I don't feel any pain. I just feel a little bit tight. Let's see what happens in the MRI tomorrow."
The timing was particularly cruel.
Tuesday marked the first time Acuña had shared the field this year with his younger brother, White Sox infielder Luisangel Acuña. The two exchanged smiles throughout the evening and even shared a moment after Luisangel applied a tag on Ronald during a stolen-base attempt.
"It was amazing," Acuña said of sharing the field with his brother. "The first time we shared the field and played together. So I'm disappointed because I don't know if I can play tomorrow and the next day."
Atlanta jumped out to an early lead behind Olson, who homered twice -- including a remarkable opposite-field blast on a changeup below the strike zone -- and finished with three RBIs.
The Braves carried a 4-0 advantage into the middle innings before Chicago chipped away. Atlanta briefly regained control when Mauricio Dubón delivered a go-ahead RBI single in the 10th inning, but Montgomery's walk-off homer against Raisel Iglesias ended it.
It was a memorable moment for the White Sox rookie.
For the Braves, however, the lasting image from Tuesday night wasn't Montgomery rounding the bases.
It was Acuña limping toward the dugout.