Carolina quarterback Cam Newton suffered a hairline fracture to a rib during Friday's preseason game against New England.
Newton suffered the injury late in the second quarter when he scrambled and absorbed a hit from Patriots linebacker Jamie Collins.
Panthers head coach Ron Rivera is optimistic Newton, who had offseason ankle surgery, will be able to play in the Sept. 7 opener at Tampa Bay.
Newton threw 24 touchdown passes and ran for six more scores last season. He completed 61.7 percent of his passes for 3,379 yards.