WALTHAM, Mass. -- Boston Celtics president of basketball operations Danny Ainge said Kevin Garnett is battling inflammation in his injured left ankle and estimated the team will give him two weeks off to recover.

Ainge believes that Garnett initially injured the ankle against New Orleans on Wednesday, then played on it in Dallas on Friday.

Garnett, who missed practice Monday, sat out Saturday's game in Memphis and underwent an MRI when the team returned to Boston.

Initial test results didn't alarm team doctors, but Ainge noted the team is being overly cautious to ensure a healthy Garnett for the start of the postseason.

"I'll guess two weeks, just because we want to make sure he's really ready," Ainge said of Garnett's recovery timeline.

Added Ainge: "I think it happened in New Orleans game, it was just sore -- just inflammation. A lot of things can cause inflammation; I think everyone has a little bit of inflammation this time of year. KG, we need to get him fresh anyway."

Guard Courtney Lee also sat out practice Monday with a sprained left ankle but was listed as probable for Tuesday's game against the visiting New York Knicks.

"Courtney could play tomorrow," coach Doc Rivers said.

Garnett is officially listed as doubtful for Tuesday.

Rivers, asked if he was worried about a long-term injury to Garnett, said he wasn't concerned Garnett would miss the rest of the season.

"No, I don't worry about that," Rivers said. "Can he miss four, five games? Yeah, that's possible."

Rivers added that he wants Garnett to fully heal.

"Whatever they decide, if they give me option of, 'You can play him every third game or give him two weeks' rest,' I can tell you right now, I'm going to say two weeks' rest -- if it's my decision," he said. "They usually never leave it up to me, but if it was my decision, that's where I would go. Because at the end of the day, I want him right and I don't want him half-right."

Rivers said he'll have to get creative with lineups, likely mixing personnel based on matchups.

The Celtics will go big with Jeff Green playing a guard-like role at times.

"When Kevin's out, especially with all the stuff we have going on right now -- you don't just have Kevin out, if you really look at it, Jared [Sullinger] was starting before he left, you have three of your five starters out [including Rajon Rondo]," Rivers said. "Then you have to look at each individual game as an individual game. I do that as a whole most of the time, but I don't do that as far as game plan, most of the time. Right now, each game we have to pick how we want to play that night. That's hard with all the new guys we have here, but that's how we may have to be."

Celtics captain Paul Pierce said injuries have ravaged the Celtics this season but that the team can't lean on that as a crutch, even amid a four-game losing streak.

"You know it happens pretty much every year," Pierce said. "It's something you've got to be prepared for, but nothing [like this] I can really think of in recent memory."