The Carolina Panthers are "cautiously optimistic" that quarterback Cam Newton will be available to play Week 1 after he was injured during Thursday's preseason game, general manager Marty Hurney said Friday.

Newton has a mild sprain of his left foot, Hurney said.

He was hurt on a sack in the first quarter of a 10-3 preseason loss to the New England Patriots. Team medical staff examined Newton's left foot on the sideline after the sack, his second in three series. The 2015 NFL MVP then walked to the locker room, and the team later announced he would not return.

Newton, 30, underwent surgery on his left ankle in March 2014.

He had sat out the first two preseason games as the staff used extreme caution in his recovery from January arthroscopic surgery on his throwing shoulder. It was the second time the right shoulder had been operated on in three offseasons.