Tests revealed that Harper has a contusion on the left ankle, which comes as a result of a fouled bunt in the rookie outfielder's first-inning plate appearance.
The ball drilled Harper on the inner part of his ankle, and even though he remained in the game and played center field in the second inning, manager Davey Johnson pulled Harper at the beginning of the third, putting Roger Bernadina in center.
"They're giving him a lot of treatment for the contusion and we'll see how he responds to that," Johnson said. "But he was down hitting and trying to swing with it. Michael Morse and (Adam) LaRoche, and they said he can't even swing. He's trying like heck and he can't even swing, can't land on it. So that's why I took him out."
"But just a bruise. He'll be fine. Whether or not he plays (in the second half of the doubleheader), I'll have to see how he's walking."
Harper was clearly limping when he went out to play center in the second inning, and LaRoche said he noticed Harper was having trouble swinging during the bottom half of that frame.
"It was pretty swollen the inning after it happened," LaRoche said. "I looked at it. I told him if you can go, go, but we understand. We've all been hit like that and it hurts. If you can't get around in the outfield, go tell somebody."
Bernadina would likely start in center for tonight's 7 p.m. game if Harper is unable to play.
Meanwhile, Johnson was asked about Henry Rodriguez after the righty had another shaky performance this afternoon.
Rodriguez came on for the eighth inning with the Braves leading 1-0 and didn't record an out. He allowed a run on a single and two walks, and he also threw a wild pitch.
"He started off the game, I thought he was throwing pretty good," Johnson said. "When he's good, he's really good. And when he's not so good, he's not so good. He was awful good for those nine saves and then he kind of ... I don't know if he gets excited and tries to do too much or whatever. I know it's as frustrating for him as it is for the rest of us."
Over his first 16 appearances this season, Rodriguez pitched to a 2.45 ERA with eight saves in 10 chances and a 21-to-7 strikeout-to-walk ratio. In his 15 appearances since then, Rodriguez has a 7.94 ERA and an 8-to-11 strikeout-to-walk ratio.
Despite Rodriguez's massive consistency issues, Johnson will continue to stick by him for now. The Nats see Rodriguez's potential, and they don't want to give up on him too early only to see him put it together elsewhere.
"I'll still throw him tonight if the need arises," Johnson said.