Jermaine O'Neal's shoulder injury appears to be more serious than the Pacers first believed.

"There's no official word yet, but I'm starting to be afraid this is more serious than we hoped," Pacers coach Rick Carlisle said Thursday.

O'Neal has spent most of the week in Los Angeles, visiting doctors and getting extra opinions on his right shoulder. Carlisle doesn't know whether O'Neal will need surgery. If he does, O'Neal's already shortened season likely would be over.

O'Neal sprained his shoulder while attempting a dunk late in the first half of the March 3 game at Denver.

"Had we not been able to get Dale back on the team, we probably wouldn't have been able to win two of these last three games," Carlisle said. "He's been that important to us."