Boston Celtics center Robert Williams III underwent a successful arthroscopic left knee surgery as announced by the club this Friday. 

Contrary to the earlier reports, Williams will be shelved for an extended six to eight weeks to fully recover. With that, he will be out on the Celtics’ training camp, preseason and initial parts of the forthcoming 22-23 campaign.

This recent surgery serves as the second one that Williams has taken for six months. Back in March, the big man had an initial partial left knee meniscectomy procedure to repair his torn meniscus.

Williams averaged 10 points, 9.6 rebounds and 2.2 blocks in 61 occasions for Boston last season.