Cam Newton has been ruled out of the Carolina Panthers' Week 3 game against the Arizona Cardinals.

Kyle Allen will start for the Panthers at quarterback.

Newton aggravated a sprained left foot in his last game.

"He's actually coming along well," Ron Rivera said Friday on a conference call. "The unfortunate part was last week he was playing on a short week and the foot didn't have time to come back, as far as I understand it. It was pretty sore. It was just one of those things where we have to wait it out and see where it is [next week].

"The one thing we don't want to do is have another setback."