Wide receiver Reggie Wayne (strained groin) and defensive end Dwight Freeney (knee) both took part in Friday's practice and are expected to play. Defensive tackle Eric Foster (shoulder) also practiced and should be available against the 49ers.
Quarterback Peyton Manning saw limited work on Friday but will start. Safety Bob Sanders (knee) went through the workout and will make his second straight start.
Freeney was hurt against St. Louis last Sunday but didn't really feel the effects of the injury until Monday morning.
"I'll be out there (Sunday). My knee was a little stiff this week, but it has to be real serious for me (to miss a game)," he said. "I've got the swelling down now, so I should be all right."
If Brown doesn't play, second-year running back Chad Simpson will split time with starter Joseph Addai. Mike Hart, another second-year running back, could also play.
"What we do with them is let Joe take as many of (rushing attempts) as he wants, and when he wants to come out of there, we relieve him at that time," coach Jim Caldwell said. "(Hart) is a possibility. He's been working in practice, and he's certainly ready to go."
Copyright 2009 by The Associated Press