Williams' arthroscopic surgery removed loose bodies and address swelling in his left knee, he is expected to resume basketball activities in 8-12 weeks. Gallinari underwent a left knee revision ACL repair and further updates about his recovery timeline will be provided as appropriate.
Williams was a key contributor to the Celtics' torrid second half of the regular season and postseason run, bringing valuable energy culminating in 2.2 blocks and 3.9 offensive rebounds per game in 61 regular season starts. He 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.
On Sept. 2, the Celtics announced Gallinari had torn his ACL during a FIBA World Cup qualifier against Georgia in August. Boston signed Gallinari to a two-year, $13.5-million contract in the offseason.
Gallinari tore the same ligament in 2013. The Celtics didn't provide a timeline for his return. But such injuries typically involve a recovery process of up to a year, meaning it would be unlikely for the veteran to play this season.
-With files from Associated Press