Garnett is out two to three weeks after hurting his knee against Utah on Thursday. Garnett is out two to three weeks after hurting his knee against Utah on Thursday. (Tony Gutierrez/Associated Press)

Boston Celtics forward Kevin Garnett will miss two to three weeks of playing time because of a strained muscle behind his knee, the NBA team said Saturday.

He suffered the injury while going up for an alley-oop in the first half of Boston's 90-85 loss to Utah on Thursday. He landed awkwardly and immediately motioned to the bench for a substitute.

When the soreness in his knee persisted, the Celtics sent Garnett back to Boston as a precaution. After tests and an MRI, the team doctor diagnosed the muscle strain.

Garnett is averaging 16.3 points and 8.8 rebounds this season in 32.2 minutes of action.

Boston (44-12, first in the Eastern Conference) visits the Phoenix Suns on Sunday. The Suns just lost Amare Stoudemire for up to eight weeks with a detached retina.

With files from the Associated Press