The Oklahoma City Thunder on Sunday said Durant informed the team of "discomfort" in his right foot after practice a day earlier. He underwent tests and the team said in a statement he was diagnosed with a "Jones" fracture — a broken bone at the base of the small toe. It's unclear how the injury happened.
The Thunder said traditional treatment requires surgery, and recent NBA cases have resulted in a return to play in six to eight weeks.
"We are in the process of collaboratively evaluating the most appropriate next steps with Kevin, his representatives, and Thunder medical personnel," general manager Sam Presti said. "Until a course of action is determined, we are unable to provide a timeline specific to Kevin's case."
Presti was to discuss the injury at a news conference Sunday.
The Thunder open their season Oct. 29 at Portland. A six-week absence could have Durant back for the start of December, which would allow him to play about 65 games.
Durant won the scoring title last season, collected his first MVP award and led the Thunder to the Western Conference finals. He skipped playing for the U.S. national team in this summer's Basketball World Cup so he could get additional rest. He played in two preseason games before complaining of pain.
The Thunder were forced to play for nearly two months last season without their other All-Star, Russell Westbrook, because of a knee injury, but remained among the West's best because of Durant's brilliance.
He averaged 32 points, 7.4 points and 5.5 assists and was an overwhelming winner of MVP honours, ending LeBron James' bid for a third straight. Durant had a run of 41 consecutive games with at least 25 points, the third-longest streak in NBA history.
He has won four of the last five scoring titles, and was at his best during Westbrook's absence from late December through the All-Star break, averaging 35 points and 6.3 assists as the Thunder went 20-7.
Now it will be up to Westbrook to raise his game while Durant is sidelined, or the Thunder risk falling behind quickly in the powerful West.
Durant has been among the NBA's most durable players in recent years, missing just one game in each of the last two seasons and playing in all 66 during the lockout-shortened 2011-12 campaign, when Oklahoma City lost to Miami in the NBA Finals. He sought a break from his heavy workload this summer, dropping out of his commitment to the U.S. after taking part in the first week of their training camp.
Now he will sit down again.