Doc Rivers first developed back trouble while playing at Marquette University, and simply learned to tolerate the discomfort over the course of his career.

The Celtics coach can see his rookie forward, Jared Sullinger, following a similar path.

Sullinger, who left Wednesday's win over Sacramento due to back spasms, missed practice for the first time yesterday. Rivers termed his availability for tonight's game against Orlando "50-50," and can envision similar detours the rest of the season as Sullinger continues to absorb more games and pounding under the basket.

Back trouble, lest anyone forget, was a big reason behind Sullinger's slide down the draft chart last June. Rivers only hopes his starting power forward can learn to endure the pain like so many players before him.

"When you have a back (problem), it's all connected. It's not one thing; it's everything," said Rivers. "When you have a back spasm, I'm sure it's connected somehow. I'm not that concerned. He may miss games, but it's not anything (serious). My guess is that he plays with it every day. I had a back injury my whole career, and once you have a back, you have a back.