Coach Doc Rivers described the clash as an accident, since both Allen and Perkins were playing together, during a "skeleton" drill, which does not include a defending team.

"It was a 'skeleton' drill, no defense," Rivers said. "We thought he was goofing around when he went down. But then we saw the blood."

Allen and Perkins were working a hand-off play, Perkins keeping possession as Allen cut past him. But Perkins, holding the ball, brought his elbow down as Allen raced by.

Allen hit the ground grabbing his eye, according to Rivers who initially thought Allen was joking. “All of a sudden he was laying down and all of a sudden you saw the blood and said, ‘Oh no, I don’t think he’s faking.’”

Rasheed Wallace said the injury did not affect the Celtics energy during practice.

“We’re still going hard, still intense,” he said. “Unfortunately it happened but we can’t sit up here and be sad and be down on ourselves, like oh man Ray got hurt. No, we’ve still got to go out there and play.”