CHAPEL HILL, N.C. — North Carolina coach Roy Williams said reigning national player of the year Tyler Hansbrough is "extremely doubtful" for Saturday's season opener for the top-ranked Tar Heels.

In a statement from the school Wednesday, Williams said the team will keep Hansbrough out of practice a little longer as he recovers from a stress reaction in his right shin. Hansbrough hasn't practiced for two weeks with the injury, which can be a precursor to a stress fracture.

"It's extremely doubtful that he would play against Pennsylvania, and I emphasize extremely doubtful," Williams said. "We will continue to evaluate him and have more information when it becomes available."

Hansbrough has played in all 108 games of his three-year career, though he missed Saturday's exhibition win against North Carolina-Pembroke. It was the first time North Carolina had played without him since its win against Illinois in the 2005 NCAA championship game, and he had missed just one practice — the day after playing 47 minutes in a double-overtime win against Clemson despite an infected toe last year — before this injury.

Williams said after the game that Hansbrough had been limited to shooting free throws.

The school had said Hansbrough would be out indefinitely and that it was unclear whether he would miss any regular-season games.

If Hansbrough doesn't play, the Tar Heels would be without two starters. Top defender Marcus Ginyard is out until at least December after having surgery on his left foot.

Against UNC-Pembroke, the Tar Heels started 7-foot freshman Tyler Zeller in Hansbrough's place while Danny Green — North Carolina's sixth man last year — started for Ginyard.