Arizona Cardinals quarterback Carson Palmer left with an injured left knee early in the third quarter of Sunday's game against the St. Louis Rams.

Palmer appeared to hurt himself while planting his leg trying to avoid a sack. He was able to walk off the field, but was taken to the locker room on a cart after that.

Palmer missed three games earlier this season with a damaged nerve in his throwing shoulder.

On Friday, he signed a three-year contract extension worth a reported $50 million with $20.5 million guaranteed.

Arizona trailed 14-10 when Palmer left the game with 11:28 to play.

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