"It didn't feel very good. It got a little tense in there, and I needed a little break real quick," Harper said after the game. "Good thing our trainer got out there, gave me a second. It just definitely didn't feel right, and we'll see what tomorrow has in store for us."
Harper remained in the game and struck out to end the third inning. He ended up going 0-for-3 with three strikeouts.
"Anybody who has a stiff neck, you are not yourself, so I took [Harper] out for precautionary reasons," manager Dusty Baker said. "We'll see if it's any better tomorrow."
Bill Ladson has covered the Nationals/Expos for MLB.com since 2002 and writes an MLBlog, All Nats All the Time. He also can be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.