Stoudemire's injury was revealed during a magnetic resonance imaging exam following his early exit from New York's Saturday contest against Detroit.
Stoudemire, who is averaging 17.6 points and 8.0 rebounds per game, complained of back tightness during the game.
The 29-year-old, six-time all-star also missed time with back problems during last season's playoff series against Boston.
New York is clinging to a 1 1/2-game lead in the race for the eighth and final post-season berth in the Eastern Conference.
2014: The Year in Fashion [PHOTOS]
LeBron James reveals his new Nike shoes