Sam Cassell is joining the Celtics as an assistant coach under Joe Mazzulla, Shams Charania of The Athletic tweets.
The longtime NBA guard spent the past three seasons as a lead assistant for the Sixers under Doc Rivers.
Celtics president of basketball operations Brad Stevens ended speculation after the Eastern Conference Finals when he stated that Mazzulla would remain the head coach. However, changes were anticipated to surround Mazzulla with more experienced staff.
Cassell interviewed with the Rockets this spring for the head coaching job that went to Ime Udoka. Temple University was said to be interested in hiring Cassell as its head coach in March, but he decided to stay in the NBA. He also interviewed last year for the Jazz head coaching job.
Before his stint in Philadelphia, Cassell served as an assistant with the Wizards and Clippers. He has a history in Boston, as he was on the Celtics’ roster in 2008 when they won the championship during the twilight of his playing career.