Rookie first-round pick Chris Williams left the practice field during a one-on-one pass-rushing drill.
He was taken to the training tent and then to the locker room and coach Lovie Smith revealed he has a back injury.
It's not how the Bears wanted things to start with their prized selection.
``We'll always err in favor of the players, but it was to the point where he couldn't practice,'' Smith said. ``When I say there is some stiffness, I don't know exactly how much, but he couldn't practice. The guys know there's a difference between pain and injury. It seems like his was more of an injury.''
No word on the seriousness of it. Undrafted free agent Cody Balogh worked with the second team after Williams departed.