Philadelphia 76ers All-Star center Joel Embiid underwent successful surgery to address a fractured orbital bone in his left eye, the team released in a statement.

The 76ers said there is no timetable for his recovery and he will return when it is safe and medically cleared. He will have a post-operative exam in five to seven days.

Embiid was injured during the second quarter of the 76ers’ game against the New York Knicks on Wednesday after a nasty collision with teammate Markelle Fultz.

Fultz was driving toward the basket 20 seconds into the period when he appeared to accidentally head-butt Embiid. The 7-footer immediately went to the floor. He remained on the floor for several minutes before finally being assisted by Philadelphia’s trainer. Embiid sat up once before lying back down on the court. Eventually, he was helped off the court.

Fultz was not injured on the play.

Embiid also suffered a concussion and remains in the NBA’s concussion program.

The Sixers clearly need their big man if they’re going to make a run in the Eastern Conference playoffs. Embiid leads the team with 22.9 points and 11 rebounds in 63 games, helping Philly clinch its first playoff berth since 2012.

The Associated Press contributed to this report.