INDIANAPOLIS (AP) -The Indianapolis Colts have confirmed that cornerback Marlin Jackson will miss the rest of the season after injuring his left knee in practice.

The Colts also announced Friday that receiver Anthony Gonzalez underwent arthroscopic surgery on his right knee Thursday. It's not clear when he'll resume playing.

The team said it had placed Jackson on injured reserve for the injury he suffered Wednesday. The Colts didn't give details on Jackson's injury, but a person with knowledge of the injury told The Associated Press on Thursday that Jackson had torn his ACL.

The Colts had been anticipating a return by Gonzalez, who hasn't played since spraining ligaments in his right knee during the season opener. He caught 57 passes for 664 yards last season.