WASHINGTON -- Activated off the disabled list on Wednesday afternoon, Nationals right-hander Stephen Strasburg exited his start in the third inning of a 5-4 walk-off win over the Braves with an elbow injury.
According to manager Dusty Baker, Strasburg felt a pinch in the back of the elbow, but the team will not know what's wrong until Strasburg has an MRI on Thursday.
After Strasburg struck out Braves starter Mike Foltynewicz for the first out of the inning, Nationals trainer Paul Lessard and pitching coach Mike Maddux went to the mound to check on Strasburg. Then Lessard summoned Baker to come to the mound. Baker called it "a long walk" to check on Strasburg.
A few minutes later, Strasburg left the game and was replaced by left-hander Sean Burnett. Strasburg allowed one run on two hits over 2 1/3 innings.
Strasburg, who is 15-4 with a 3.60 ERA in 24 starts, had missed 16 games with right elbow soreness before taking the mound Wednesday. The right-hander also missed 17 games in June with an upper back strain.
Baker said that Strasburg was healthy and ready to go on Wednesday. This was Strasburg's first start since Aug. 17 against the Rockies. When he had his bullpen sessions at Citi Field and Nationals Park recently, Strasburg insisted he was fine.
"He did everything that was asked of him. He was cleared," Baker said. "He wasn't trying to be a hero. He said that he felt fine. But a lot of times you really don't know until you get into action. … We thought everything was fine, because [catcher Wilson] Ramos said he was throwing the heck out of the ball. He said his changeup was outstanding, and he had good command. And usually if something's wrong, you don't have command. So we're hoping that it's something minor, but again, we'll find out more tomorrow."

Strasburg left the ballpark and didn't meet with the media.
Ramos said he felt bad for Strasburg, who was throwing such a great game. Strasburg retired six of the eight hitters he faced. Then came that third inning.
"He was locating his pitches well," Ramos said. "His velocity was good. When he said his arm was bothering him, I felt extremely bad, especially the way the game was going for him. It was going very well."
Strasburg has had elbow problems in the past. In 2010, he had Tommy John surgery and didn't return until late the following season.
"I hope Stras is OK and it's nothing too serious," said teammate Lucas Giolito, who also went through elbow reconstruction surgery. "It's definitely a tough thing. The only thing he could do is keep looking forward.