Updated: 9/04/2014 3:32 pm
Charlotte, NC (SportsNetwork.com) - Carolina Panthers coach Ron Rivera said this week that Cam Newton's availability will be determined on a day-by-day basis.
On Thursday that meant the dynamic quarterback was a limited participant in practice, though both Rivera and Newton said the quarterback was "on pace" to start the season against the Tampa Bay Buccaneers on Sunday.
Rivera said Newton did everything they planned for him in Thursday's practice -- a day after Newton sat out because of sore ribs.
"This is a marathon, not a sprint," Rivera said.
Newton, who says he's never missed a football game, is recovering from a fractured rib he suffered in a preseason game against New England when a defender's knee caught the quarterback in a "dead spot" in his pads where there was no protection.
He said Thursday that passing is "sometimes manageable" and other times not, but that he's not currently in pain. The injury makes it hard to sleep and make sudden moves, among other things, and the variety of passes he has to throw can sometimes be challenging, Newton said.
He was optimistic that he'd be ready to play against the Bucs, but cautious about hurting himself or the team by rushing back.
"If I can go, I'm going to go. And how I'm feeling right now, I'm on pace to be ready to go on Sunday," Newton said.
The former No. 1 draft pick led all NFL quarterbacks in rushing attempts (111) and yards (585) last season during Carolina's run to the NFC South title. He set career bests with 24 touchdown passes and a 61.7 percent completion rate.