Okafor confirmed reports of the injury via Twitter.
Arizona lost its starting outside linebackers Sam Acho (broken leg) and Lorenzo Alexander (foot injury) in Sunday's loss to the New Orleans Saints. They were placed on season-ending injured reserve on Monday.
Okafor, a fourth-round draft pick out of Texas, said in his tweet that he would be back next year "stronger than ever."
The Cardinals are practicing in Bradenton, Fla., this week in preparation for Sunday's game against Tampa Bay.
Copyright 2013 by The Associated Press