Kevin Garnett's sore right knee has led the Celtics to decide to shut him down until the playoffs approach.

Doc Rivers made the announcement on Tuesday after practice and the All-Star forward won't return until the final few games of the regular season.

Celtics president Danny Ainge insists that there is no need to worry about Kevin Garnett's lingering knee injury.

"Nothing has changed from our initial diagnosis to where we are now," Ainge said on Monday. "We're just being cautious."

Garnett will miss his 15th game because of the injury on Wednesday night, but Ainge contends that his condition hasn't worsened.

"This isn't a setback," Ainge said. "Not at all."

Boston is looking at Friday's game against Atlanta as a possible return date.

"We're still evaluating the process," Ainge said. "This is still a day-to-day evaluation. I think KG is playing great. He doesn't feel 100 percent, and you can see that. But the more rest we can give him, the better off we are going to be in the long run."

Celtics forward Kevin Garnett did not play on Sunday against the Thunder, and is expected to skip Wednesday's game against the Bobcats because of a lingering knee strain.

"I just think we've got to be smart about it," coach Doc Rivers told the Boston Globe. "It's just like when somebody says somebody is going to be back in a week or two, that's not a guarantee. If a guy gets sore, do we play him because we say he's supposed to be back playing? You just use your common sense. Put it like this, he would have to be very good for me to play him. He won't be out long. We've got two days (Monday and Tuesday) off and, hopefully, by the end of the week."

Celtics point guard Rajon Rondo doesn't believe that the Hawks are one of the team's rivals.

"I don't think much of it really," Rondo said of a possible rivalry. "I don't like to talk trash, but in my eyes it's not a rivalry. I don't know if anybody else looks at it as a rivalry. People consider Cleveland a rival. We just went seven with Atlanta. That's about it."

The Hawks, who will battle the Celtics on Friday night, tend to disagree.

"That it's Boston is always a big deal because they're still the champs," said forward Josh Smith. "They get that from everybody until someone wins the title this year.

"But it's even more important for us because we've got to get our swagger back here at home. We need to keep that magic flowing here and not let that slip away."

Kevin Garnett has stepped in to defend teammate Stephon Marbury, who he spent time with as a member of the Timberwolves as well.

"Steph's leadership I think has been sort of questioned and damaged, if you will," Garnett said. "But once a leader, always a leader. I've been telling some of the young guys who haven't seen a lot of Steph that I thought we got a steal in grabbing him.

"Obviously, for whatever reasons, his different relationships with different ballclubs was a thing of the past. If you look at some of the guys on this team, they haven't always had the best reps before coming. But we deal with each other how we deal with each other, and he fits right in.

"Not only is he versatile, but people forget that Steph was one of the premier guards in this league for a while. And other than him not playing for a year, we all expect big things out of him. But I think he expects a lot of big things out of himself. He works extremely hard. You just don't, excuse my French, be the (expletive) from a point guard standpoint, all them years of being who you are. Obviously, the facts are there, but you just don't become that. You get that through hard work, watching film. I know what kind of drive he has inside, and I think he's going to help us in the long run."

Celtics coach Doc Rivers said that he hopes to increase Kevin Garnett's minutes on Monday against the Clippers.

Garnett played less than 15 minutes on Friday night against the Spurs, his first game in several weeks, and appeared to handle his time well.

He is Boston's third-leading scorer with 16.2 points per game and leads the team in rebounds with 8.7.

Garnett played 17 minutes on Saturday night against the Grizzles.

The Boston Celtics announced today that they have reassigned rookie guard J.R. Giddens to their NBA Development League affiliate Utah Flash.  This is the third time this season that Giddens has been assigned to Utah.

Giddens has appeared six games this season for the Celtics scoring four points in eight total minutes. Giddens has averaged 17.6 points, 5.7 rebounds, 1.27 steals and 1.40 blocks per game in 15 games for the Flash this season.

Celtics coach Doc Rivers has been fined $25,000 by the NBA for publicly criticizing referee Bill Kennedy after the team's loss to the Bulls on Tuesday night.

"Amazing," Rivers told the Boston Globe in a text message. "What can I say? It reminds me of the song, 'How can something feel so right yet feel so wrong.' "

Kennedy also was fined an undisclosed amount for his conduct toward Rivers, according to an NBA source.

With Boston trailing, 124-119, following a timeout with 29.8 seconds left in the game, Rivers received his second technical foul and was ejected. He claims that he was baited by Kennedy.

"The technical on which I got thrown out was the most unprofessional technical by a ref I've ever had," Rivers said after the game. "He stood there and goaded me and goaded me and stared at me. Look at the film. I actually walked away.

"He asked me, 'Where do you want the ball?' And I said, 'Ask them,' talking about my players. That's my right to say that. He stood there and stared me down and stared me down and goaded me until I turned around and said, 'What?' That's when I got thrown out of the game. In a [5-point] game? Think about that."

Kevin Garnett hasn't played in more than a month, but Celtics president Danny Ainge believes that the star is close to returning.

"He's looking good," Ainge said. "He's made a great deal of strides, especially in the last 10 days or so. It took him a little while to get going. But in the last week to 10 days, he's been looking a lot better.

"Just by the way he's moving, he looks fresh and healthy. We're still playing it by ear. We're still waiting to see what's going to happen. I'm confident that he will be back [soon]."

Garnett suffered a sprained right knee on Feb. 19 against the Jazz, and has not practiced yet with the team.

Doc Rivers and the Celtics are not expecting to be able to catch the Cleveland Cavaliers for the top seed in the playoffs.

"We've earned the record that we have right now," he said. "We're not going to catch Cleveland, but we still have a chance to hold onto the second part of that. The bottom line is these are not injuries where guys are not going to come back - they are going to come back - and we have time to put the pieces together. We know the picture of the puzzle, we just don't have the pieces in place. We'll get them together, it's just going to take time."