Zion Williamson, arguably the most highly anticipated N.B.A. rookie since LeBron James, won’t play in his first regular season game until at least December as he recovers from an injury to his right knee.

Williamson had arthroscopic surgery Monday to fix a torn lateral meniscus, the New Orleans Pelicans said Monday. He is expected to miss six to eight weeks.

Initially, Williamson’s injury, believed to have been suffered in a preseason game against the San Antonio Spurs on Oct. 13, was described as “soreness.” Now, the league is missing one of its main draws as it attempts to move past an ugly rift with the Chinese government with a splashy start to the regular season.

The N.B.A. had scheduled the Pelicans against the Toronto Raptors as its opener on Tuesday night as part of a prime-time doubleheader. The Raptors won a title last season, but lost their best player, Kawhi Leonard, to the Los Angeles Clippers in free agency.