(Paul Sancya/AP)

“It sucks,” said John Lannan, the starting pitcher who figures to replace Wang in the event the injury sidelines him. “He’s been throwing his butt off. Hopefully, there’s no setback. Hopefully he’s okay and he can make his next start. You hope and pray that he didn’t do anything.”

The testing likely includes an MRI, Manager Davey Johnson said. Wang injured his hamstring fielding a groundball in the third inning, a dribbler that he scooped up on his way to first base. Wang hyperextended his knee as he ran to touch first base, and he crumpled to the ground.

“I could tell right away when he got up and he was limping, that was it for him,” Johnson said. “I hope it’s not serious. He was throwing the ball exceptionally well. I was pleased with what I was seeing. It just reaffirmed the fact that he’s back. So it was a really tough break to see that happen.”

First baseman Chad Tracy stood behind Wang as he fielded the ball and was the closest Nationals player to him when he fell.

“You could see his leg quivering,” Tracy said. “He didn’t want to put any weight any weight on it. You could tell he was hurting. But I don’t know what’s going on with him. Hopefully, he’s all right.”

Yankees catcher Russell Martin hit the groundball and leaped over at first base as Wang collapsed.

“I asked him if he was alright,” Martin told New York reporters. “He kind of shook his head like, you know, ‘I’m not feeling too good.’ It happened in slow motion. It was weird.”