PITTSBURGH – Braves star Ronald Acuña Jr. exited Sunday’s game early after injuring his left knee in the top of the first inning.

When Acuña was on second base, he began running toward third after the catcher threw the ball back to the pitcher, but quickly stopped and, as he turned back toward second, crumpled to the ground. He was in clear pain.

The Braves won’t know more until Monday, manager Brian Snitker said. Acuña must receive imaging and go through a full evaluation.

But Acuña seemed to feel optimistic that this injury is not as serious as when he tore the ACL in his right knee in 2021. He did say the Braves will put him on the 10-day injured list, though.

“(We) think (compared to the one from Miami), this one is not that hard,” Acuña said through interpreter Eddie Perez, a Braves coach. “It doesn’t feel that painful and I didn’t hear any pop or anything, so I’m feeling good. We don’t think it’s that bad.”

The Braves are calling it “left knee soreness” for now. But Acuña said he’ll undergo imaging on Sunday night and won’t know the full extent of the injury until Monday.

“I don’t know how bad it is until we get it looked at,” Snitker said after Sunday’s win over the Pirates. “It’s very concerning. When he went down like that, you think the worst. But I don’t know, like I say, until they get him looked at.”

After Acuña fell to the ground, assistant athletic trainer Nick Flynn and manager Brian Snitker went out to Acuña. Third base coach Matt Tuiasosopo also walked over, then first base coach Tom Goodwin did the same.

When it happened, Acuña was concerned.

“Yeah, I was scared a lot, because I felt the pain in the beginning, but it’s been going away for a while,” he said.

Acuña compared Sunday’s injury to the mild sprain of his left ACL in 2018 – which he suffered sprinting to record an infield single. He missed a month with that injury.

“I think I’m gonna miss the same amount of games,” Acuña said.

Acuña was on the ground for a couple of minutes on Sunday, then got up and slowly walked off the field. He was limping as he did so.

The injury occurred with one out in the top of the first. Acuña led off the game with a double before that.

Here is Acuña’s explanation of the play:

“I saw the catcher throwing the ball back to the pitcher very slow, and then I was timing (it) so I could steal third. But in that moment, he threw it hard, and I had to come back. That’s when I felt it.”

The Braves and Acuña should know more on Monday, which is why Snitker didn’t have many answers after Sunday’s game.

“Well, he walked off (the field),” Snitker said. “Yeah, absolutely concerned. We’re not going to know anything until we get him looked at and we can’t right now.”

Can Acuña walking off the field be considered a positive sign?

“I don’t know,” Snitker said. “It doesn’t even do me any good to comment on it until we get him looked at.”

Still, this is a scary situation. Acuña is a crucial part of Atlanta’s lineup. The Braves won a World Series without him in 2021, but their chances are much better with him leading off.

There will be concern until the Braves know more – even if Acuña seemed to think he avoided the worst-case scenario.

“It’s tough, man,” Chris Sale said. “You never want to see anybody, on either side of the field, do that. He’s a big part of this team. He’s one of the best players in the league. We’ll be all right, but you’re hoping for the best right there.”

Before Acuña’s injury, it was realistic to think the Braves might be back at full strength on Monday, with Austin Riley and Sean Murphy potentially returning to the lineup.

Instead, this is another unfortunate circumstance in a season full of them to this point.

“It’s just something that everybody goes through,” Snitker said of the injuries. “We’ve been through it before. Personally, I hate it for the young men that it affects more than us. These guys love to play the game. When something happens to those guys, I hate it for the individuals more than us, quite honestly.”