Boston Celtics centre Robert Williams is scheduled to have an arthroscopic procedure on his left knee which is expected to require four-to-six weeks to recover, according to ESPN's Adrian Wojnarowski.
Williams played in 61 games last season for Boston averaging 10 points, 9.6 rebounds and two assists per game. Williams was also one of Boston's top defensive players according to NBA stats as he had a defensive rating of 103.4 points per 100 possessions.
The 24-year-old had surgery back in March to repair a torn meniscus and would return for Game 3 of the Celtics' first-round series against the Brooklyn Nets.
Boston was also without Danilo Gallinari who suffered a torn ACL in his left knee while playing for Italy during a FIBA World Cup qualifier against Georgia last month. The Celtics signed Gallinari to a two-year, $13 million contract in July.