Fortunately for him and the Nationals, he wasn't seriously hurt, and according to Adam Kilgore of The Washington Post, Harper is in the lineup tonight.
Your Nats right fielder tonight: Bam Bam Harper. He's in the lineup.— Adam Kilgore (@AdamKilgoreWP) May 12, 2012
OK, everyone, he's alright, it's cool to laugh now.
Harper was 0-for-5 for the game; after his fourth at-bat he smashed his war club against the clubhouse wall, it rebounded and smacked him on the noggin, right above his left eye.
It opened up a cut that required 10 stitches to close, but doctors have given him the OK to play.