Harper has been one of the most productive position players on the Nationals lately, going 13-for-41 (.317) with two home runs and six RBIs in his last 10 games.
"I'm trying to find ways to get playing time [for some of the guys]. Their playing time has been cut short. I want to get Tyler Moore in," Johnson said. "With Harp, I kind of run him into the ground. I'm sure he is not tired. I think he was a little tired on Sunday [against the Cardinals], for some reason. He felt great yesterday against the Cubs."
Right fielder Jayson Werth will also get the day off on Wednesday, Johnson said.