"Anybody that's had a stiff neck realizes how tough that is, especially to swing," Baker said. "He's on a day-to-day basis."
Baker said the team suggested Harper avoid swinging a bat, because doing so could risk worsening the injury. Harper has said he first felt pain in his neck late last week. He played all nine innings Friday, then came out after six on Saturday.
Chris Heisey started in right field Tuesday in Harper's place, batting sixth.
Alex Putterman is a reporter for MLB.com based in Washington.