Trestman has confirmed that Cutler will not play in next Sunday's match against the Baltimore Ravens, but revealed that the 30-year-old was no longer suffering from the torn groin muscle he picked up earlier in the season.
"I think you all know he's got a high ankle sprain. He got it rolled on. It was unrelated to the groin injury. It happened in the second quarter," Trestman told reporters.
"They taped him up. There was no indication from the trainers there would be any further injury. I thought offensively he had one of his best games. I asked [the trainers] if the groin was an issue at all, [and they] didn't feel that there was.
"They told me even today, if he hadn't rolled up the ankle, he would have been able to play today."
Meanwhile, Trestman has admitted that he kept Cutler in the game for too long while he was injured.