Harper, who was 3-for-3 with a walk and two RBIs, was able to walk off under his own power. Manager Matt Williams said after the game it was a precautionary move.
"Given the state of that game, get him out and get some ice on him right away," Williams said. "Hopefully he's good to go [Sunday]."
Harper was replaced by outfielder Matt den Dekker and was the third Nats' batter to be hit by a pitch during the game. Brewers manager Craig Counsell denied that it was intentional.
"That's just a ball that got away," Counsell said.