Chicago Bears quarterback Jay Cutler missed practice on Thursday and his playing status remains in question because of a concussion.
Coach Lovie Smith said Cutler continues to improve, but it's not clear if he'll be ready to play at San Francisco on Monday night.
If Cutler can't play, Jason Campbell will likely start.
The Bears believe Cutler was injured on a helmet-to-helmet hit from Houston's Tim Dobbins late in the second quarter of Sunday's loss. He finished the half but sat out the final two quarters after showing symptoms in the locker room at the break.
Cutler needs to be cleared by team physicians and independent neurological consultants before he can return. The same goes for teammate Shea McClellin and 49ers quarterback Alex Smith, who also suffered concussions last week.
Lovie Smith gave mostly vague answers about Cutler.
When asked if he expects his quarterback to practice on Friday, saying, "Wait 'til tomorrow and see."
He also left open the possibility of Cutler playing without practicing this week, assuming he gets cleared. But he wouldn't say if the Bears would hold out their quarterback even if the doctors gave the OK to play.
"I can't wait for us to get to the point where Jay is ready to play and we'll make all those decisions then," Smith said. "First just (get him) ready to practice and then we'll go to that next step."
Defensive tackle Henry Melton said Cutler "looks like the same old Jay." When he'll be able to play is another issue.
The Bears crumbled after Cutler broke his right thumb in the 10th game last season, finishing at 8-8 after a 7-3 start, but they believe they have a solid backup this time in Campbell. He could be tested this week by one of the top defenses in the league.
49ers backup QB Colin Kaepernick could face a similar situation against the Bears.
Lovie Smith said not knowing which quarterback they'll be facing impacts both teams.
"I think it helps if you know exactly who you're preparing for," Smith said. "There's an advantage on our part if they don't know that Jay's playing. There's an advantage on their part that we don't know if Smith is playing. I think you look at that a little bit, but eventually you get to trying to defend the quarterback position. That's what we're doing. They're going to have somebody underneath center that we'll have to be able to contend with."
While Cutler and McClellin sat out Thursday, receiver Alshon Jeffery practiced on a limited basis. He injured a hand against Jacksonville on Oct. 7 and has missed the past four games.
Online: http://pro32.ap.org/poll and http://twitter.com/AP_NFL