Durant suffered the injury early in the Warriors 112-108 loss to the Washington Wizards on Tuesday when teammate Zaza Pachulia fell backwards into his left leg.
He was taken to a Washington area hospital where he underwent an MRI, which revealed Durant had suffered a Grade 2 medial collateral ligament (MCL) sprain and a tibial bone bruise.
The Warriors, who have the best record in the league at 50-10, said in a statement posted on the team's Twitter feed that Durant will be re-evaluated in four weeks and could play again before the end of the regular season.
Durant, the 2014 NBA most valuable player, rocked the league last year when he left the Oklahoma City Thunder to join reigning MVP Stephen Curry to form a Dream Team in Oakland.
He leads the team in scoring (25.8 points per game), rebounding (8.4 rpg) and blocks (1.7 bpg).