Kony Ealy will start in his place.
Allen expressed frustration over the decision as he walked out of the locker room, saying he was "disappointed" and feels healthy enough to play.
Rivera says it was a difficult decision, saying Allen is a "warrior."
Allen broke a bone in his foot in the fourth quarter of Carolina's 31-24 win over Seattle last Sunday.
Allen practiced on Thursday raising some hope that he might play.
Rivera he's hoping Allen would be ready to play in two weeks in the Super Bowl if Carolina were to win Sunday.