Harper is out of the lineup for the Nationals' series opener against the Indians, a somewhat surprising development given the way he and the team downplayed the significance of the injury when it first became public Saturday night.
"It's the same thing," manager Dusty Baker said. "We were hoping that these couple days (would help). A stiff neck, he's been getting worked on and stuff. Anybody that's had a stiff neck realizes how tough that is, especially to swing. He's on a day-to-day basis."
Harper, who did not appear in the clubhouse this afternoon while reporters were present, did take the field with his teammates for stretching exercises, but did not play catch or take batting practice. He had a noticeable brown mark on the back, right side of his neck, presumably the byproduct of treatment he has been receiving to alleviate the pain.
Baker suggested the team actively instructed Harper not to do much physical activity today, wanting to give himself a chance to heal through rest.
"He was trying to do (more) before," Baker said. "We suggested he shut it down, because he could be making it worse. ... Just have to wait to see. I don't have any more to tell you. I know it's big news, but I don't want to just make up something."
Mired in a prolonged slump since May, Harper had shown signs of a possible breakthrough last week, with a flurry of well-struck balls in consecutive games. But he struck out in all three of his at-bats Saturday night, and had to pause during the second one after appearing to injure himself on a foul ball, prompting a visit from head athletic trainer Paul Lessard.
Harper stayed in that game for another three innings before getting pulled before the top of the seventh. He said afterward he had been dealing with a stiff neck for "a couple days" but was uncertain how long it would take to recover to the point he could play.
"I'm not sure," he said. "It's a stiff neck. That's not the greatest for baseball. Definitely tough, but I'll try to come in here tomorrow and see where we're at."