"It's not responding as well as he'd like it to respond," Williams said of the shoulder, which McLouth injured diving for a ball on July 28. He went on the disabled list a week later with what the team called inflammation.
The 32-year-old has tried to do strengthening exercises on the shoulder and has received a cortisone shot, but the injury has reportedly not improved.
"It's not going quite as well as he'd like it to go. Doesn't mean it won't," Williams said. "Sometimes it takes longer than you would normally like. But he's going to go get a second look at it and see what that doc has to say, and then we'll make a determination from there what the next step would be."
McLouth is hitting a career-low .173 with one home run and seven RBIs in 79 games this season. The 10-year veteran of the Pirates, Braves, Orioles and Nats has 101 career home runs with a .247 batting average.
- Chris Mascaro