Carson Palmer exits with knee injury

— -- GLENDALE, Ariz. -- Cardinals quarterback Carson Palmer left Sunday's 31-14 win over the St. Louis Rams with a left knee injury early in the fourth quarter, just two days after signing a three-year, $50 million extension.

He was listed as questionable and did not return.

Palmer was injured on a sack by Rams safety Mark Barron with about 11:21 left in the fourth. Barron hit Palmer but didn't bring him down. Palmer went to the turf a moment later and lay on the field while he was attended to by team trainers and doctor. While he was walking off the field, he appeared to stumble and had to be held up. He was then carted off the field.

Palmer was 25-of-36 for 241 yards, with no touchdowns and just his third interception of the season before exiting.

He tore the ACL and MCL in his left knee during a playoff game with the Cincinnati Bengals in 2006.

Information from The Associated Press was used in this report.