A two-time Pro Bowl pick, Vanden Bosch has been bothered by a strained groin since Oct. 5, so Dave Ball started at right defensive end. Outside linebacker Keith Bulluck was available to play in his 106th straight game after cracking cartilage in his ribs in last week's overtime win against Green Bay.
Orton said he hoped to play after being taken from the field on a cart with a sprained right ankle late in the first half of last week's win over Detroit. So the Bears went with former starter Rex Grossman, who was making his first start since Dec. 6.
He lost a preseason competition with Orton and got booed as soon as he stepped on the field last week. Then, Grossman delivered an erratic performance. He threw a touchdown pass in the third quarter and scored the go-ahead TD in the fourth, but was 9-for-19 with 58 yards and an interception.
Chicago was also without wide receiver Brandon Lloyd (knee) and linebacker Hunter Hillenmeyer (thumb). Safety Mike Brown, who left the Lions game with a right calf injury moments before Orton went down, was active. So was cornerback Charles Tillman, who has been bothered by a shoulder injury.