Chicago Bulls forward Patrick Williams will undergo surgery to repair a dislocated left wrist and is expected to miss the rest of the regular season, sources told ESPN.

Williams tumbled out of the air on a flagrant foul by New York’s Mitchell Robinson on Thursday night, landing on his left wrist and suffering a severe perilunate dislocation, the source said.

There’s hope that a timeline on a return could make it possible for Williams to return for the playoffs, a source told ESPN. The reshaped Bulls are off to a 4-1 start this season.

The loss of Williams represents a significant blow to Chicago, which has been counting on the No. 4 overall pick in the 2020 NBA Draft to play a significant role this season. Williams missed most of the preseason after suffering a sprained ankle.

After leaving Florida State as a freshman for the NBA, Williams, 20, showed flashes of promise his rookie season, but struggled with consistency. A strong performance in the NBA summer league had the Bulls hopeful that he could make a leap in his progress this season alongside Zach LaVine, Lonzo Ball, DeMar DeRozan and Nikola Vucevic.