The Bears lost to the Dallas Cowboys, 41-28, on Friday night; the team's second consecutive loss moves it to 5-8 this season.
Trestman was asked on Friday if the team would give backup quarterback Jimmy Clausen more playing time in Chicago's three remaining games. According to comments from Trestman, unless Cutler was forced out of the lineup by injury, he would remain the starting quarterback.
"Jay [Cutler] is our quarterback," Trestman said. "If he's available to play, he's going to play. Jimmy is continuing to work in the offense, and he practices."
"We certainly like having [Clausen] on our football team, but but as we get ready for New Orleans next week, Jay will get the reps and he'll be playing."
Cutler, 31, with nine years in the league, completed 69 percent of passes against Dallas, throwing for 341 yards and two touchdowns and one interception. He added one rushing touchdown. This season, he has passed for 3,446 yards, 26 touchdowns and 15 interceptions.
He signed a seven-year deal worth $126.7 million in January, and currently leads the NFL with 21 turnovers and, prior to the game against Dallas, was 30th of 34th quarterbacks with a 49.5 completion percentage on passes longer than five yards.
"I think we evaluate his performance game by game, and then when the season's over, we evaluate the year," Trestman said. "So I don't go into the statistical aspects of what he did this week or the next week. It's how did he play yesterday, and how will he play next week? Really, that's the only way we look at it..."
Clausen has appeared three times for the Bears this season, the last time on Nov. 9, in Chicago's 55-14 loss to the Green Bay Packers. He has not started since the 2010 season, when he completed 52.5 percent of his passes for 1,558 yards, three touchdowns and nine interceptions in 13 games with the Carolina Panthers.
The Bears, currently fourth in the NFC North, host the New Orleans Saints on Dec. 15, at 8:30 pm EST.