Dennis Schroder was fined $25,000 for his low blow on P.J. Tucker during Oklahoma City's game five loss to the Houston Rockets.
Tucker was also fined $25,000 for his role in the confrontation, in which he headbutted the back of Schroder's head.
The Rockets reportedly wanted the league to investigate Schroder's actions, and were upset that no action was taken after Chris Paul's low blow on Ben McLemore earlier in the series.
The Rockets lead the series 3-2.