Durant injured the toe Saturday in the second quarter against the Charlotte Hornets after stepping on an opponent's foot. He finished the game, playing 35 minutes with 29 points and 11 rebounds in the Thunder's 109-90 victory.
The Thunder said Durant woke up sore Sunday and will see how he feels over the next few days. There is no timetable for Durant's return, but he's likely doubtful for Wednesday's matchup against the Memphis Grizzlies, although coach Billy Donovan said he didn't consider it serious.
"Obviously with Kevin out, that's a huge [deal] for our offense," Russell Westbrook said before Monday's game. "But as a team, I thought we've done a good job of moving the basketball around, and tonight we've just got to continue to move the ball around. The ball will find open shots."
Durant suffered a sprained left big toe last season against the Cleveland Cavaliers, which caused him to miss four games. Durant, of course, played in only 27 games last season because of a series of injuries, including three surgeries on his right foot to repair a Jones fracture.
The Thunder (24-11) are 21-7 this season with Durant, outscoring opponents by 15.1 points per 100 possessions with him on the floor. Without him, they're now 3-4.
"It definitely helped having KD out," said Kings power forward DeMarcus Cousins, who had 33 points and a season-high 19 rebounds. "That's a big threat that they didn't have tonight. It made our jobs a little bit easier on defense. I think we were able to key in on Russ tonight and make other guys shoot, and we won the game."
Durant, 27, missed six games in November after spraining his hamstring against the Washington Wizards. In 28 games this season, Durant is averaging 26.6 points, 7.4 rebounds and 4.6 assists.
The Associated Press contributed to this report.