The team announced Thursday that Williamson will miss the preseason finale because of right knee soreness. No timetable was provided for his return.
The Pelicans traveled to New York for their matchup against the Knicks, but Williamson didn't make the trip with the team. The standout forward will remain in New Orleans to undergo additional testing, according to the Pelicans.
Williamson has made appearances in all four of the Pelicans' preseason games this year, averaging 23.3 points and 6.5 rebounds in 27.3 minutes per game.
During the summer league, Williamson played only eight minutes after he sustained a minor left knee bruise. The team was cautious with the former Duke Blue Devils star and shut him down as a precaution.
Williamson, who didn't miss any time during training camp, also suffered a mild right knee sprain while playing for Duke. His Nike sneaker gave out seconds into a game against the North Carolina Tar Heels, causing him to miss six games.
The Pelicans open their regular-season schedule against the defending NBA champion Toronto Raptors on Oct. 22.