Cam Newton has been ruled out of the Carolina Panthers' Week 3 game against the Arizona Cardinals as he recovers from a foot injury.

Newton aggravated a left foot sprain in Week 2 against the Tampa Bay Buccaneers and has not practiced this week. 

The 30-year-old initially injured his foot during pre-season, forcing him to miss nearly a week of practice. 

Kyle Allen, a second-year quarterback who went undrafted in 2018, will start in place of Newton, who was in a walking boot in the locker room on Thursday, though his prognosis beyond this week is not clear. 

"He felt pretty good at the end of the week," coach Ron Rivera told reporters on Friday. "But we don't want another setback. [We] want to make sure he's ready to roll."

Newton's absence comes after he struggled against the Buccaneers, completing just 25 of 51 passes for 333 yards and no touchdowns in a 20-14 loss.

Allen has taken the first-team snaps all week to prepare for the possibility of Newton being sidelined. 

The 23-year-old played in the final two games of last season, earning a start in the Panthers' season finale against the New Orleans Saints, leading the team to a 33-14 win.