Quarterback Cam Newton has a hairline fracture in one of his ribs, and has been ruled out of the Panthers preseason finale in Pittsburgh. Head coach Ron Rivera expects his team’s most-important player to be ready for the regular season opener two weeks from Sunday in Tampa Bay, but that’s certainly not a guarantee.

“There is a lot of concern. This morning he came in, and he was very, very sore,” Rivera said after Sunday’s practice, one Newton watched while walking the sidelines gingerly. “We expect him to get past the soreness the next few days, and then be able to do a lot more as the days go.”

Newton, who’s still not 100 percent after offseason ankle surgery, took a knee to his back and rib area after scrambling during the second half of the Panthers preseason loss Friday in New England. After going back to the huddle, Newton went to a knee and eventually came to the sideline, missing the next play. He finished the second quarter and played the opening series of the second half despite the injury.

Last week, the fourth-year player said “I’m not a sliding type of guy,” but it may finally be time for Newton to avoid the hits he’s so readily taken.

“He had a chance to make a play on it, he chose to tuck it and run, and one of the things he’s going to have to learn is either dump it or slide,” Rivera said. “That’s him; that’s who he is. He tries to get everything out of it, and it’s unfortunate it was one of those fluke things that happened.”