Just when Bills CB Terrence McGee appeared to be taking a few steps forward in his recovery from patella tendon surgery, he took a significant step backward.

Coach Chan Gailey said that McGee suffered a setback during Monday’s practice session and the veteran will not return to the field this week.

“His knee got a little weaker in practice yesterday, so we’re sitting him and seeing where he goes,” Gailey said. "He’s not going to play this week, so we’ll have to see where that takes us."

With two youngsters currently starting at cornerback -- first-round pick Stephon Gilmore and second-year pro Aaron Williams -- the Bills were hoping that McGee would be able to contribute in some form at the start of the season. McGee has been a dependable performer throughout his career when healthy, but the injuries have been adding up in recent years. He has tarted 91 of 115 games played since 2003 but has missed 16 games over the past two seasons. Before the setback, McGee said he was around 90 percent.

Gailey said McGee’s long-term availability is a concern.

“Yeah, I mean you always are [concerned],” Gailey said. “Until a guy can go out there and play consistently and have no setbacks you get worried. I’ve got a lot more confidence with where Eric Wood is than I do with Terrence McGee because Eric has had no setbacks [from ACL surgery]. Terrence has had a couple of setbacks during the course of camp and preseason practice.”

Gailey did not believe that the injury would put McGee on the bubble to make the roster.

“I don’t see that right now, no,” he said.

Anderson, Pears updates: The Bills hope that two key starters -- DE Mark Anderson and RT Erik Pears -- will be healthy enough to return in time for the team’s season opener. Both have been dealing with groin injuries. Anderson’s injury appears to be the lesser of the two, but Gailey believes both should be back in time to play.

For more updates on the Bills follow correspondent Mark Ludwiczak on Twitter @CBSSportsNFLBUF and @MarkLud12.