Thomas said he, like the coaches, are concerned with his knee. But, he added, that’s nothing new.

“I’ve been having concerns with my body for four or five years,” he said. “That never stopped me from playing a game. I love the concerns. That just pushes me to prove them wrong. If that keeps a little doubt in people’s head, that makes me look better when I’m out there. … I’ll never be 100 percent the rest of my life.”

Thomas participated in the nine-on-nine portion of practice, but did not take part in the full-team work. He said he’s not certain if he’ll play Thursday night vs. Baltimore.

Thomas underwent arthroscopic surgery on his right knee in May.

“I don’t want this thing to blow up on me. I can admit I’m [33] and it’s going to take a little more time,” he said.

Will Montgomery • 6-3, 305 pounds

The Centreville native continues to have a strong camp as the No. 2 center. He’s doing a good job holding his ground and anchoring in pass protection. Montgomery — whom some in the organization say is playing with more attitude — also must show he can play guard, but has primarily worked at center this camp.

Edwin Williams • 6-3, 315 pounds

The ex-Terrapin has done a decent job at center, working with the No. 3 line. However, he needs to show a lot more at guard if he wants to make the roster. Williams is OK at setting up on pass drops, but he needs to get quicker so he can move in space. He also needs to improve his ability to pull at guard.

PLAYER OF NOTE

Devin Thomas • WR

Thomas did not practice again because of his sore hamstring, but did catch passes and run sprints (but not at full speed) following practice. Thomas said he’s not sure if he’ll play against Baltimore on Thursday. His big problem comes when he has to plant and cut. Thomas was supposed to bump Antwaan Randle El from the No. 2 role, but he has to show he’s worthy of that spot. Thus far, that hasn’t been the case.

QB WATCH

Jason Campbell

One thing that would help Campbell is a big target at receiver, something he has lacked since joining the Redskins. Receivers like that can turn errant passes into completions. Malcolm Kelly did that for Campbell Monday morning. The 6-foot-4 Kelly stretched far to his left to snag a misfired pass from Campbell. The key will be keeping Kelly healthy — but if he is, his long arms and size provide Campbell a wide radius for his passes.