Cox was released by the Seattle Seahawks a day after he was signed by the club, replaced on the roster by DeShawn Shead.
Seattle made the roster moves on Wednesday. Coach Pete Carroll had indicated on Tuesday that Shead would be promoted from the practice squad to the active roster, but waiving Cox came as a surprise. Seattle signed Cox on Tuesday after cornerback Walter Thurmond was suspended four games for violating the league's substance abuse policy. Cox started the season with San Francisco, but was waived by the 49ers in early November.