Oklahoma City guard James Harden was listed as day-to-day on Monday after taking a blow to the head on Sunday, but the Oklahoman newspaper reported that he will not play in either of the Thunder's final two regular-season games.
Harden will be re-evaluated on Tuesday.
He sustained a concussion when he was hit the head by an elbow from Los Angeles Lakers forward Metta World Peace.
Harden fell to the court and stayed down for a few minutes. He did not return to the game.
"Harden participated in a series of limited activities per NBA guidelines, but has additional steps that must be taken under the league-mandated concussion policy before he can make his return to the court," the Thunder said in a statement.
The NBA has not yet announced whether World Peace will be punished.
Harden is averaging 16.8 points, 4.1 rebounds and 3.7 assists this season.