But on Monday night in Minnesota, they'll try to take advantage of a Timberwolves team they've won 11 straight against. Ten of those victories have come since Garnett was traded to Boston in the summer of 2007.
The Celtics (38-35) have lost six of eight overall and six of seven on the road following a 108-89 defeat against the Knicks on Sunday. They remain in seventh in the East, 2 1/2 games back of Atlanta and 2 1/2 in front of Milwaukee.
Sunday was their fifth straight game without Garnett, who has been sidelined with inflammation in his left ankle. Coach Doc Rivers said Friday that the team was intending to stick to its initial two-week timetable for Garnett's return, which would likely see him miss two more games this week against Detroit and Cleveland in addition to Monday's contest.
The absence of Garnett -- Boston's leading rebounder with 7.8 per game -- has had an effect on the boards, with the Celtics giving up an average rebounding margin of minus-4.8 over the last five. Garnett is also the club's second-leading scorer averaging 14.9 points.
Boston could also be without leading scorer Paul Pierce (18.7 ppg) on Monday after he turned his ankle during Sunday's loss.
"I feel like when we're healthy we can compete with anybody," said Jeff Green, who scored 27 against the Knicks and is averaging 20.2 points on 52.5 percent shooting over his last 10 contests. "We have a chance on it, whoever we match up against."
Despite being long removed from the playoff hunt, the Timberwolves (26-46) have been more competitive recently, splitting their last six games, including an impressive victory over Oklahoma City on Friday.
It seemed they were on track for another surprising win Saturday against Memphis, but they allowed a 16-2 run at the beginning of the fourth quarter on the way to a 99-86 defeat.
"I just think at one point we looked like we were trying to win the game in one possession," coach Rick Adelman said. "Trying to making hero plays and super plays. Just try to make solid plays."
Nikola Pekovic is listed as questionable after sitting out against the Grizzlies because of the sprained left ankle he suffered Friday, the latest in a litany of injuries for Minnesota this year.
The Timberwolves have seen a positive with Ricky Rubio continuing to look more like he did before tearing his ACL last March. He's averaging 13.8 points and 8.6 assists over his last 28 games, compared to 5.5 points and 5.4 assists in his first 19 games back from the injury.
Boston's offense has slowed to a crawl away from home, averaging 88.7 points over its last seven road games. The Celtics have also struggled to defend the 3-point line of late, allowing their last three opponents to go 29 of 64 from beyond the arc (45.3 percent), though the Timberwolves rank last in 3-point percentage (30.0).
The Celtics claimed a 104-94 home victory in the season's first meeting Dec. 5. Pierce and Garnett each scored 18 points as Boston shot 52.6 percent from the floor, though Rubio was still sidelined for Minnesota.