Montgomery

Both players are out four to six weeks, a 49ers spokeswoman said.

McQuarters was hurt returning a second-quarter kickoff.

"I saw the hit coming and I tried to get my shoulder into it," McQuarters said. "He hit the shoulder dead-on, and I knew as soon as he hit it something was wrong."

Mariucci said the team would make roster moves on Tuesday to replace McQuarters and Montgomery.

Two 49ers defensive ends also were injured. Gabe Wilkins suffered a right foot strain and Jeff Posey bruised his left hip. Both are probable for Sunday's game at Cincinnati.