Porter has been ruled out for Thursday's game against the Buccaneers due to an illness, Todd Archer of ESPN.com reports.
Only days after his trade from Pittsburgh to Dallas this past Sunday at Houston, Porter was able to handle a 45 percent snap share but didn't make any marks in the box score in his Cowboys debut. An illness will keep him sidelined in Week 5, though, allowing Ameer Speed and Caelen Carson to work at outside cornerback opposite DaRon Bland.