WALTHAM, Mass. - Kevin Garnett isn't ready to start the playoffs, and Boston Celtics coach Doc Rivers said Thursday that there's a strong possibility that he will miss the entire postseason.

"He's not going to be ready. After watching him practice, there's no way," Rivers said on WEEI-AM. "The way I saw him move today, I don't know if he'll be ready."

When asked to clarify, Rivers said there was a chance Garnett could be out for the rest of the season. Celtics spokesman Jeff Twiss said he could not elaborate on Rivers' comments.

Garnett injured his right knee Feb. 19 and missed the next 13 games before returning for four, but never playing as many as 18 minutes. With the Celtics assured of a high playoff berth, Rivers then held Garnett out with an eye toward bringing him back for the last three games of the regular season; that became the last two, then the last one, but he never made it back.

Rivers said Thursday he watched Garnett run at the team's practice facility and said he had to shut him down after 20 minutes.

"If he can't get through biking and working out without swelling and his leg locking, I don't know how you can play in the playoffs," Rivers said. "This was an honest run today, you couldn't make your way through it. The guy's a warrior, you see him try to mask his way through it. But after 20 minutes of running, I don't see it. After today, there's no way he can play."

Garnett's reaction?

"He was frustrated. He was mad at me, mad at everybody. Then he understood," Rivers said. "He put up a fight. He's really frustrated, but that's Kevin. That's why we got him, because he cares so much."

The defending NBA champions begin the best-of-seven first round series against the Chicago Bulls on Saturday.

"We're going to move on without him," Rivers said.

A service of the Associated Press(AP)