After the half inning ended, Harper left the game and was replaced by Tyler Moore who went to left field, while Jayson Werth switched from left to right field.
Harper had X-rays taken and the results were negative. It's not known if Harper will play Sunday afternoon against the Giants.
"I got it pretty good," Harper said. "I hurt my ankle and it went down my foot. I felt pretty terrible at the time. It's still pretty bad. I'll know the status in the morning and go from there."
Bill Ladson is a reporter for MLB.com 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.