Danny Green left the game due to a left knee injury and did not return.
Sources told Adrian that the injury Green suffered is serious. The full extent of the damage was to be determined by an MRI.
The 76ers were eliminated from the playoffs after a 99-90 loss on Thursday night.
Green, who will turn 35 next month, suffered the injury when 76ers center Joel Embiid accidentally fell into his left leg after attempting a shot. After grabbing at his leg in pain, Green was helped to his feet and carried to the locker room.
The crowd chanted his name as he was carried off, and then audibly gasped when the replay was shown on the board.
Green, in his 13th NBA season, has been a critical piece in Philadelphia's playoff run. He entered the starting lineup full time late in the season when he was asked to do so by the Toronto Raptors. Through 11 games in the playoffs, Green hit 40% of his 3-pointers and averaged almost 29 minutes per game.
The series is in danger of being eliminated on Thursday night.