Cutler was examined by team and independent doctors after practicing on a limited basis Wednesday, and the decision was made to have him sit this week.
Cutler went through another limited practice Thursday and declined comment afterward. He's also expected to practice again Friday and have his status re-evaluated next week.
Veteran Todd Collins, who took over to begin the second half against the Giants and left with a stinger, will make his first NFL start in three years.
"I'm pretty comfortable," Collins said. "The best way to provide leadership, I think, is to go out there and perform well. That's the job as the quarterback, to move the ball and score points. That's what I'm going to try to do to help lead the team."
Collins said Smith told him late Thursday morning that he would start -- news that he expected.
"Jay went down with a concussion, and usually with concussions, they want you to come back fully ready before you get on the field again," Collins said.
This will be the first time that Cutler has missed a start because of injury. He had made 57 in a row since the Denver Broncos turned to him as a rookie in 2006, but he'll watch this weekend after a brutal performance against the Giants wiped out much of the goodwill created by the Bears' 3-0 start.
"I'm not going to sit here and say it doesn't hurt," wide receiver Devin Hester said. "It does hurt."
Smith said the Bears started noticing concussion symptoms in Cutler after the second-to-last play of the second quarter, when the quarterback's head banged the turf while cornerback Aaron Ross took him down on the Giants' ninth sack.
But Cutler started taking a beating as soon as he stepped on the field. On one sack early in the second quarter, Giants defensive end Osi Umenyiora ran past Bears tight end Greg Olsen and nailed Cutler from behind, popping the ball out and into center Olin Kreutz's arms.
Cutler got up and took a few steps toward the wrong sideline before correcting himself.
Soon after, Cutler had what appeared to be a dazed look when television cameras showed him sitting on the sideline, and his decision-making was questionable at best. Cutler held onto the ball too long at times and didn't see open receivers, and he wound up taking hit after hit.
It didn't help that the Giants also had a clear path to the quarterback.
If he's worried about taking a beating, Collins wouldn't say.
"If you're thinking about the protection and the offensive line, you know I've got better things to worry about than that because you simply can't control it," he said. "You've got to let those guys do their job, and I'm going to try to do mine and get the ball to the playmakers."
Collins, 38, has endured long stretches with little activity since he entered the NFL in 1995 with the Buffalo Bills. He has barely played since he helped the Washington Redskins win their final four games in 2007.
Collins took over for injured starter Jason Campbell during a 24-16 victory over the Bears that season and threw for two touchdowns after going three years without attempting a pass. That came just 1½ weeks after the shooting death of safety Sean Taylor and three days after his burial.
The Redskins closed that season by winning the next three games with Collins, but he didn't take a snap in 2008 and made just three appearances as a backup in 2009. He was released last March and signed a one-year contract with the Bears in late August.
"I've been around for awhile," Collins said. "It's a team game, but I look forward to going out there and doing my part, contribute to a victory."
Copyright 2010 by The Associated Press