SANTA CLARA The Bears removed all doubt Friday, announcing that backup quarterback Jason Campbell would start Monday's game in San Francisco in place of starter Jay Cutler.
The situation is not as clear with the 49ers' concussed starting quarterback. For the third straight day, Alex Smith practiced in a black jersey worn by players who are returning from concussions but who haven't been cleared for game action.
San Francisco coach Jim Harbaugh said Smith continues to show progress but stopped short of saying the quarterback would start against the Bears.
"Again, it's in the doctors' hands, and they'll evaluate him as the week goes," Harbaugh said. "There seems to be some progress."
Harbaugh said backup Colin Kaepernick was getting "a little bit more work than normal" in case Smith isn't ready.
Campbell started for the Raiders for two years and is very familiar to 49ers cornerback Carlos Rogers, who played with Campbell at Auburn and with the Washington Redskins, who selected both of them in the first round.
Rogers said the 49ers aren't taking a different approach to the game with Cutler on the sideline.
"I think both of them have strong arms, the ability to throw any throw," Rogers said. "We know what Cutler can do. I played with Jason for a while. I know what he can do. We don't look at them as being any different. They both can throw the ball; they both can scramble. As a defense, it's easy to prepare for those guys when we're looking at them the same way."
Hefty fine The NFL fined 49ers defensive end Ray McDonald $21,000 for helmet-to-helmet contact with Rams quarterback Sam Bradford on Sunday.
McDonald was penalized for roughing the passer on the play and could have been penalized for the same thing after making contact with Bradford three plays later.
Neither Rams linebacker Jo-Lonn Dunbar nor 49ers safety Dashon Goldson received fines.
Dunbar struck Smith in the shoulder and the back of the helmet on a quarterback run in the first quarter. The blow may have contributed to Smith's concussion. Smith, however, didn't slide on the play, which made the hit legal.
Goldson was penalized for unsportsmanlike conduct for removing his helmet on the field.
Masifilo exits The 49ers are looking for a new practice-squad player after rookie defensive tackle Matthew Masifilo was signed by the Buccaneers.
Masifilo, who played for Harbaugh and defensive coordinator Vic Fangio at Stanford, was one of the team's first cuts. The 49ers brought him back before the preseason finale against San Diego after another defensive lineman was injured, and Masifilo excelled in the game.
He will join former Stanford and 49ers teammate Chris Owusu in Tampa Bay.