Johnson said that Wang underwent tests Thursday night that confirmed the strain and added that Wang has dealt with an injury like this in the past. But Johnson is not necessarily ruling out the possibility that Wang, slated to be the Nationals' No. 5 starter, could be ready to go for his first turn in the rotation.
"He can still throw, he can still play catch, he can still maintain arm strength and even build on arm strength," Johnson said before the Nationals' 4-3 loss to the Yankees in 10 innings at Steinbrenner Field. "Looking on the positive side, it's probably not a bad thing to have a little breather, because he's come so far. That's not the worst thing that can happen.
"All this panic mode about, 'Will he start the season?' -- that's a pretty good ways [away]."
According to Wang, there isn't a timetable on when he will return to action.
"We are going to treat it as much as we can, and then we'll let the team doctor evaluate a couple of days later," Wang said. "We'll see what we can do from there."
Wang spent most of Friday in the trainer's room getting treatment. Asked how he was feeling since the injury occurred, Wang said, "This morning, I feel the same like I did yesterday. So far, I don't feel worse. So I feel it's OK."
With no score and one out in the third inning on Thursday, Yankees catcher Russell Martin hit a soft ground ball toward first base. Wang fielded the ball and fell down awkwardly after an initial misstep, then collided with Martin while coming across the base.
"I was trying to pick up the ball and, in one step, I felt like I [hyperextended] my knee," Wang said. "And then ... I was trying to run [to first base]. I couldn't do it. I had a little funky motion at that point. I tried to pick up the ball and finish the play."
Given the awkward way Wang landed on his shoulder and how he appeared to have rolled an ankle or hyperextended something, Johnson was initially worried the injury would be more serious. Still, Johnson said he doesn't "fool with hamstrings," especially since Wang wouldn't have to start from square one in terms of getting stretched out for the season.
"I'm concerned any time a guy goes through something like that," Johnson said. "Then, when he got up with a slight limp, that was it. That didn't worry me as much."
Wang pitched well on Thursday prior to the injury, throwing 2 2/3 scoreless innings, allowing two hits and a hit batsman, while striking out four.
"The story from yesterday should be about his arm and about the way he threw," Johnson said. "I expected it, and he even surpassed my expectations, the way he was going at it. I didn't expect to see that kind of stuff until the end. Maybe it was the Yankees, and he got a little adrenaline going, I don't know. But I was real impressed. I was expecting it, and I was still impressed."
If Wang isn't ready to make his first regular-season start, left-hander John Lannan, the subject of many recent trade rumors, figures to become the Nationals' fifth starter.
Aside from Wang being the fifth starter if he's healthy, Johnson was not ready to reveal the order of the rest of his Opening Day rotation as of Friday morning.