WASHINGTON (AP) — Nationals right-hander Jason Marquis went on the disabled list Wednesday with an injury to his pitching elbow.

Washington general manager Mike Rizzo said Marquis told the team in the morning that his elbow stiffened up the night before. An enhanced MRI exam showed there are "some floating bodies in the elbow," Rizzo said.

Marquis, 0-3 with a 20.52 ERA, will get a second opinion Thursday. He failed to record an out in his last start, letting all seven Milwaukee Brewers he faced Sunday reach base in what became an 11-7 loss for Washington.

Rizzo wouldn't say who will replace Marquis for Friday's game against the Dodgers but did say it's a pitcher currently at Triple-A Syracuse. The expectation is that it will be right-hander Luis Atilano, who never has pitched in the majors.

Asked if the injury explains Marquis' struggles, Rizzo said: "I'd imagine it does. It's hard to pitch with floating bodies in your elbow. He's probably trying to gut it out. In my opinion, it probably does have something to do with his poor performance."

Marquis, Rizzo and Nationals manager Jim Riggleman all have said in recent days that the starter was healthy.

On Monday, Rizzo said: "I can only go by what he tells me and what I see when he's on the mound and throwing his bullpens and that type of thing. He says he feels great. His arm is working fine."