Harper followed up a seventh-inning groundout back to Cincinnati pitcher Jose Arredondo by swinging his bat against a wall in the Washington dugout area. The bat bounced back and hit him above eye level, on the left side of his head.
"It's just a little frustration," said Harper, whose hair was still blood-stained as he spoke with reporters at his locker. "It doesn't hurt at all. I feel fine. I didn't get light-headed."
Harper went hitless in five at-bats, including striking out three times in the Nationals' 7-3 win at Great American Ball Park. It was just the second time in his 12 games in the Major Leagues that he failed to reach base at least once. Harper remained in the game after the incident, had a final at-bat in the ninth inning, and then was replaced in right field by Xavier Nady as part of a double-switch with pitcher Sean Burnett.
Harper said he got the doctor's clearance to play, and that he expects to be available against the Reds on Saturday night in the second game of the three-game series. Manager Davey Johnson wasn't as quick to pencil him into the lineup.
"It wasn't the bat splintering. It actually came back and hit him in the head, so I'm sure there's going to be some swelling in there," said Johnson. "I'm not going to take any chances. We'll see how it is [Saturday], but more than likely he'll miss a couple of games."
The cut was originally tended to with some butterfly bandages, but the blood flow continued until Harper received the stitches.
"He was very frustrated that he was not centering the ball, and that's what ballplayers do -- break bats," said Johnson. "Now I'm only going to let him throw helmets. That's not anything new. It's an easy way to get rid of your frustrations."
Harper has picked up a nickname because of the incident. Shortstop Ian Desmond has dubbed him "Bam Bam".
Harper has shown frustration before in the Minor Leagues, but the 19-year-old has shown a cool resolve since the Nationals called him up from Triple-A Syracuse on April 28. If getting thrown at intentionally is old-school baseball, so is beating up dugout equipment.
"I've done this a number of times, but this has never happened," said Harper. "I guess I won't do it anymore, but I don't know. I've done it a million times. It was heat-of-the-moment kind of thing. It just came back and got me."
Kevin Goheen is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.