Heat guard Jason Williams was back in the lineup Sunday against the Blazers, but no one can say for sure when he'll next have to sit out.

Chronic right knee tendinitis has hampered Williams all season, forcing him to miss 10 of 35 games. Williams was a key part of the Heat's four-team trade last season, but so far he has been a part-time starter at point guard for the Heat.

"A lot of guys have tendinitis," said coach Pat Riley, who engineered the trade in his role as team president. "But we didn't think it was going to be a problem."

Williams, 30, is under contract for three seasons after this one. Williams, who has never missed more than 10 games in the past three seasons, has said he has dealt with tendinitis for a while now but wasn't sure when it first flared up.

Riley already had limited Williams' practice activity. Now he said he would restrict Williams even more, blaming Williams' scratch from the game at Phoenix on Friday on a hard practice the day before.

"No practice, that's all, I guess," Riley said. "I don't think we can practice him at all in a way that is going to be hard. ... I think you have got to be even more conscious."