Veteran Josh McCown, who completed 36 of 47 passes for 352 yards, two touchdowns and one interception in the Bears' 42-21 loss to the St. Louis Rams, will make his fourth start of the season Sunday versus the Minnesota Vikings.
"Jay remains week to week and I don't expect him to play on Sunday," Trestman said. "There's nothing other than a high-ankle sprain involved here. I want to make that very clear."
Trestman insisted that Cutler will return this season. The quarterback has been receiving constant treatment on his injured left ankle and could be available when the Bears host the Dallas Cowboys on Monday, Dec. 9.
"I'm totally confident he'll play again this season," Trestman said. "I don't have any reason [not to be] based on what I've been told. It's still week to week. I'm confident, and I think Jay is confident.
"You have to leave yourself an opening, but there is no underlying information here. [The injury] is week to week with the understanding that at some point in time, on a week-to-week basis, that he'll be back."
Cutler reiterated that Dec. 9 was "the goal."
"I'd be pretty disappointed if I wasn't able to play for that game," Cutler said Monday during "The Jay Cutler Show" on ESPN 1000. "I've been out long enough. So hopefully this time next week, we're having a different conversation, and I haven't been ruled out on a Monday."
Cutler said he's spending most of his time improving mobility in his injured ankle, in addition to doing exercises to strengthen the area. Cutler is using an ARP machine to speed recovery, as he did after tearing a muscle in his groin during an Oct. 20 loss to Washington.
"If I'm not playing next week, I'll be pretty disappointed," Cutler said. "I will be playing either in that Monday game [against the Cowboys], or whoever we play after that. Let's lean toward the Monday game, though."
Trestman also said starting tailback Matt Forte suffered a slightly hyperextended right knee against the Rams and will be evaluated Wednesday.
Forte managed to finish the game and carried the ball 16 times for 77 yards and caught seven passes for 40 yards, but the former Pro Bowl rusher spent the majority of the postgame open locker room period in the trainers' room and was one of the last Bears to leave the stadium and board the team bus to the airport.
"We're optimistic about [Forte's injury], but you just have to wait and see in these cases," Trestman said. "We'll know a lot more on Wednesday."
Briggs has not played since suffering a small fracture in his shoulder against the Redskins, and Paea sat out the Rams game after re-injuring his toe in Week 11, an ailment that caused him to skip two additional games earlier in the season.
Defensive tackle Jay Ratliff (groin) will continue to practice with the hope of making his Bears debut sometime in the next couple weeks.
Information from ESPN.com's Michael C. Wright was used in this report.