"I did what I could to get loosened up," said Harper, who went 0-for-2 before exiting in the bottom of the fourth. "I didn't do very well afterward. I'm going to see [the physical therapist] tomorrow, get loosened up a little bit more and see if I can get out there."
Harper is having a career year, hitting .331 with 31 home runs and 78 RBIs.
• Center fielder Michael Taylor, who sat out on Wednesday because of a sore right knee -- the same knee he injured after crashing into the wall last Thursday against the Padres -- will be re-evaluated on Thursday to see if he can start the series opener with the Braves.
"He was OK through batting practice," manager Matt Williams said. "Then, toward the end of BP, it started to get to the point where he couldn't bend it very well. We'll see how he reacts tomorrow. If it's still bothering him, we may get a picture [MRI] of it."
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.