Coach Lovie Smith said Friday that Forte "is making a lot of progress," but isn't ready to play. Forte went to the locker room midway through the third quarter of last week's loss at Green Bay after he appeared to twist his right ankle while being tackled by Charles Woodson. That leaves Chicago without one of its top offensive players.
He also missed the final four games last season because of a sprained collateral ligament in his right knee.
With Forte out, Michael Bush figures to be the primary ball carrier on Sunday. And, he gets a chance to show he's more than a power, short-yardage back, and that he can produce between the 20-yard lines.
"Hopefully I can get people to get that knock off me about not being an every-down back," said Bush, who signed a four-year deal with the Bears after running for 977 yards with Oakland last season. "I can't please everybody. It's a business. It is what it is. You don't like me, so what? I'm going to keep playing hard."
Bush also believes he has something to prove to the coaches.
"The more I get to play, the more I get to show them," he said. "The more they trust in me, believe in me and give me more opportunities. For the most part I know they're behind my back regardless. That's a good thing."
Besides ruling out Forte, the Bears also list defensive end Julius Peppers as probable. He sat out Wednesday's practice because of a foot problem, but was listed as a full participant on Thursday and Friday.