"I think we need a lift at quarterback. We need a spark," Trestman said, adding that the "weight of the world shouldn't be on the shoulders of Jimmy Clausen."
"He [Clausen] is going to get a chance to play, and I'm hoping that our team, against a very good defense...that there will be some response from our football team," Trestman said. "I'm looking forward to seeing how it unfolds."
Trestman said he personally informed both quarterbacks of the switch Wednesday prior to meeting with general manager Phil Emery, insisting the call to send Cutler to the bench was "ultimately my decision."
"It's a coaching decision," Trestman said. "It's [a] 46-man roster [decision]. Everybody was made aware of the process, and that was finalized with my discussions with Phil last night and with our staff. That decision on the 46 [man roster] is ultimately mine."
Cutler said he was "shocked" at first at the benching and then "disappointed."
"I didn't see it coming," he said. "But any time you lose a lot of games and don't do as well as you hoped, there's a chance that could happen."
Cutler paused for a moment when asked if Trestman's decision was fair.
"There's a lot in that question," Cutler said. "I haven't really thought about it that deeply. All I know is there is a lot of money involved in my contract, which comes with a lot of expectations, and a lot of responsibility. Whenever you're not winning and performing the way you should there's a likelihood that can happen [being benched]."
Trestman said the benching is just for this week at this point and that Cutler would be active and serve as the backup in Sunday's game against the Detroit Lions.
"We're not playing well enough at the quarterback position on a consistent basis," Trestman said.
Asked if he could play for Trestman next season, Cutler said, "Yes ... but we'd have to work on some things in the offseason that we could easily identify."
"That's not out of the question, in my book anyway," Cutler added.
Cutler has struggled this season in leading the Bears to a 5-9 record.
In Monday's 31-15 loss to the New Orleans Saints, he threw for two touchdowns but had three interceptions to bring his NFL-leading totals to 18 interceptions and 24 turnovers. He produced a season-low passer rating of 55.8 and generated a total QBR of 6.8, which registered as his second-worst performance of the season in that category (he had a 6.0 QBR in Week 10 against the Green Bay Packers).
He also was sacked a season-high seven times against the Saints.
Cutler's contract could be a big reason for the quarterback's benching, according to ESPN NFL Insider Mark Dominik.
The deal calls for Cutler to be paid $15.5 million in 2015. A $10 million guarantee kicks in on March 12, the third day of the 2015 league year, if Cutler is on the Bears' roster. If Cutler is injured at that time, the Bears will owe him $10 million in 2016.
By sitting Cutler the final two games of the season, the Bears guarantee he won't get injured and will have the ability to cut him or trade him after the season, basically saving the team $10 million.
Cutler was asked where he'd like to play next season.
"I would like to stay here," he said. "I really like it here. I love the guys in the locker room I get to play with. Clearly, it's a different set of circumstances now. Looking forward, this is the place I want to be."
However, Cutler conceded the franchise may be wavering in its commitment to the quarterback less than a year after inking a seven-year extension.
"It's a fair question. I don't know if I can answer that," Cutler said. "I think that is something for Phil [Emery], or the McCaskeys, or Trestman. In my role right now, I have to support Jimmy, and try to help him as much as possible. But of course, I wonder [about my future here]. That's a natural response to wonder.
"Going forward, it is what it is. Whatever happens, after the season or in March ...we'll cross that bridge when we get there."