Fourth-year running back Kahlil Bell is fighting for what limited playing time will be available behind Matt Forte and Michael Bush, and he's got competition from Lorenzo Booker and Armando Allen.
"Kahlil is having a great camp," running backs coach Tim Spencer said. "Every year that I've been here he's always had a great camp. He only had one situation where he (fumbled).
"I'm staying on him because I'm being real conscious of the way he carries the ball because to me that's the issue. But he gives great effort, and so I have only good things to say about him."
But Bell found little running room in the first half Thursday night, picking up just 4 yards on 4 carries, and he caught 1 pass for 1 yard. He finished with 11 rushing yards on 6 carries.
Pedal to the metal:
Dane Sanzenbacher and Eric Weems face stiff competition at the wide receiver position, and their special teams contributions could be the deciding factor when it comes to final decisions on the 53-man roster.
"A lot of guys contribute on special teams, but Dane and Eric Weems are right there with those guys," quarterback Jay Cutler said.
"They make a hard case to cut either one of those guys because they'd definitely get picked up somewhere else, and they're definitely going to contribute somewhere else if we do let them go."
Sanzenbacher, the star of last year's camp as an undrafted rookie, believes he needs to be even better this year, and he had 2 catches for 15 yards.
"He does have to be better and he has been better," wide receivers coach Darryl Drake said. "I've been very pleased with what I have seen from him."
Running back Michael Bush, another veteran unrestricted free agent brought in to provide more firepower for the offense, was ineffective with 3 carries for 2 yards.
He also mishandled a perfect pitch from Campbell that was recovered by the Broncos' Von Miller and returned 16 yards to the Bears' 6-yard line, setting up Matt Prater's 28-yard field goal that opened the scoring.
The offense ran just eight plays in the first quarter, which netted 6 yards and went to halftime with 41yards on 20 plays.
Leaving a Bear:
After signing a one-day contract Wednesday, so he could retire as a Bear, nine-year NFL veteran defensive end Alex Brown was recognized on the field prior to the preseason opener.
Brown spent eight seasons with the Bears, who drafted him in the fourth round out of Florida in 2002. He started 16 games for the Saints in 2010, his last season.
"This is the team that gave me my opportunity to fulfill the dream that I had ever since I was a small child," Brown said. "They gave me an opportunity, and I came out and played as hard as I could for them each and every weekend. I gave it everything I had. I have no regrets when it comes to football.
"I thank the McCaskey family, coach (Lovie) Smith and everybody that had anything to do with making this possible. I'm indebted to them forever."
For his career, Brown played in 143 games and started 123. He had 522 tackles, 59 tackles for losses, 45½ sacks, 5 interceptions, 16 forced fumbles and 12 fumble recoveries. His 43½ sacks as a member of the Bears are fourth most in franchise history.
Starting with the second game of his rookie season, Brown never missed a game, and he started all 16 games in seven of his nine seasons.
Nicked up again:
Starting strong safety Major Wright, whose first two NFL seasons were hindered by minor injuries, suffered a hamstring injury midway through the first quarter that isn't believed to be serious.