Source: Orton suffers high ankle sprain, out a month

The "good Rex, bad Rex" debate returns to Chicago.

Bears quarterback Kyle Orton was taken from the field on a cart late in the second quarter Sunday, and a source told ESPN's Michael Smith that a high ankle sprain will sideline him at least a month.

Rex Grossman started the second half for Chicago and led the Bears to a 27-23 come-from-behind win over the Detroit Lions.

Orton will have an MRI on Monday, the source told ESPN.

The Bears were trailing 23-13 when Orton scrambled to his right in the closing minute of the first half. Cory Redding hit him and Dewayne White fell on Orton as the quarterback was hitting the turf.

Orton got up and took a few steps, then crumbled to the ground. He was tended to for several minutes before being carried off. He was 8-of-14 passing for 108 yards.

The Bears also lost safety Mike Brown to a calf problem late in the first half.

Grossman threw for a touchdown and ran for another as the Bears outscored the Lions 14-0 in the second half. He had lost the starting job to Orton in training camp after an uneven 2007 campaign.

"I always thought odds are I was going to play a little bit, so we'll see what happens," Grossman said.

Information from The Associated Press was used in this report.