Boston Celtics swingman Mickael Pietrus was strapped to a stretcher and wheeled off the court Friday night after falling on his back during the second quarter of a game at Philadelphia.

Pietrus was driving into the paint when he was knocked backwards after 76ers guard Lou Williams got a piece of the ball, which Pietrus was holding up.

Although his lower-to-mid back hit the floor, Pietrus immediately grabbed the back of his head, which didn't strike the hardwood.

He remained on the ground for a while before being stabilized and lifted onto a stretcher.

Pietrus missed the first two-plus weeks of the season after having right knee surgery. He entered Friday's game averaging 6.9 points and 3.0 rebounds this season.