George will sit out of the contest due to right shoulder soreness. Sources told The Oklahoman that the small forward's soreness came in the Thunder's 121-112 loss to the Denver Nuggets on Tuesday night.
The team hasn't announced a replacement for George in the starting lineup. Dennis Schroder entered into the starting five the last time George missed a game.
George has only missed one contest this season. He didn't play against the Phoenix Suns on Dec. 28 with a right quad contusion.
George scored 25 points with eight rebounds and seven assists against the Nuggets. He is averaging 28.6 points, 8.6 rebounds and 4.3 assists in 36.6 minutes per game through 59 games this season.
The Thunder and Sixers tip off at 8 p.m. EST at Chesapeake Energy Arena in Oklahoma City.