Bunting against Braves starter Ben Sheets in Game 1, Harper fouled the second pitch of the at-bat, an 89-mph fastball, off his ankle. He was examined by the Nationals' training staff and got a look from manager Davey Johnson before resuming the at-bat.
"I didn't think I had broken something," Harper said. "Pain doesn't really get to me much. I think if he would've left me in there, I could've played, definitely. I've broken bones before, I've played with a sprained ankle. It takes a lot to take me out of the game."
He struck out swinging on the next pitch and went back out to center field for the second inning, but Roger Bernadina took his place in the third. Bernadina also started the nightcap, going 5-for-7 with a run and an RBI on the day.
Manager Davey Johnson said he didn't have much hesitation about inserting Harper into Game 2.
"I didn't ask him [if he was OK to pinch-hit]," Johnson said. "I just said, 'Go get loose.' And he went down and I said, 'You OK? How about defense?'"
Harper received treatment for the bruise, after he was having trouble swinging in the batting cage during the first game.
"Yeah, it was pretty swollen," first baseman Adam LaRoche said after seeing Harper's ankle. "The inning after it happened, I looked at it. I told him if he can go, go. But we understand; we've all been hit like that, it hurts. If you can't get around in the outfield, go tell someone."
The Nationals badly need Harper to stay healthy, after designating two outfielders (Xavier Nady and Rick Ankiel) for assignment this week. They're already operating with just a four-man bench, though Bernadina has been excellent in a pinch lately.
"Just focus, use the whole field," Bernadina said. "I know my ability and I put work in. They give me a chance now and then, and I do whatever I can to help the ballclub."
Harper, an All-Star in his rookie year this season, is hitting .270 overall, with eight homers, 26 RBIs and 12 stolen bases through 73 games.