Allen likely will start Sunday's game at Arizona if Cam Newton (foot) is unable to play, Brendan Marks of The Charlotte Observer reports.
During last Thursday's loss to the Buccaneers, Newton aggravated the mid-foot sprain that plagued him late in the preseason. He was seen in a walking boot Monday and didn't take the practice field Wednesday, increasing concerns about his immediate availability. Allen made two appearances when Newton was absent down the stretch last season, completing 20 of 31 passes for 266 yards and two touchdowns. Assuming he gets the nod Sunday, Allen could be in line for a productive outing against a Cardinals pass defense that has given up 309.5 yards per game through two weeks.