Gordon Hayward suffered a horrific dislocated ankle and fractured tibia in the Celtics' season opener against the Cavaliers Tuesday in Cleveland.

Hayward underwent surgery Wednesday night and is expected to miss the rest of the season, his agent told ESPN. 

"This is a setback,” Celtics coach Brad Stevens told reporters Tuesday. “We’re expecting a full recovery and we know there are going to be a lot of tough days ahead on that recovery but, at the same time, hopefully he’ll improve day-to-day, but it’s been tough. It’s been tough for him.”

Hayward jumped in an effort to catch an alley-oop pass but came down badly after colliding with LeBron James. Medical officials rushed to the floor and put his leg in an air cast before taking him off the court on a stretcher. He left Quicken Loans Arena in an ambulance on the way to the airport to fly back to Boston. 

Hayward was picked up in free agency this offseason by the Celtics. He signed a four-year, $127 million contract. Hayward had two points and a rebound at the time of his injury.