Former Philadelphia 76ers assistant coach Sam Cassell has agreed to join the Boston Celtics' coaching staff under Joe Mazzulla, The Athletic reported Sunday night.

Cassell spent the last three seasons with the 76ers after also serving as an assistant with the Los Angeles Clippers (2014-15 to 2019-20) and Washington Wizards (2009-10 to 2013-14).

Following the Celtics' loss to the Miami Heat in Game 7 of the Eastern Conference finals last Monday, the Boston Globe reported that three assistant coaches on Boston's staff were expected to head to Houston to work under Ime Udoka.

Udoka served as the Celtics' head coach for the 2021-22 season and led Boston to the NBA Finals, where they lost to the Golden State Warriors in six games. He was then suspended by the team during the offseason for "multiple violations of team policies" that centered around an inappropriate relationship with a woman within the organization.

Ben Sullivan, Mike Moser and Garrett Jackson are reportedly the three assistants that plan to join the Rockets, according to USA Today Sports. That report also indicated that Houston, along with a handful of other teams, is also interested in Aaron Miles, another Celtics assistant coach.

Cassell, 53, will be making his return to Boston, where he won a title in his lone season with the Celtics (2007-08). He averaged 7.6 points and 2.1 assists in 17 games (one start) for Boston after appearing in 38 games (33 starts) for the Los Angeles Clippers earlier that season.

In 15 NBA seasons, Cassell posted career averages of 15.7 points, 3.2 rebounds and 6.0 assists in 993 games (690 starts) with eight teams, including the Milwaukee Bucks (1998-99 to 2002-03). He was an All-Star in 2003-04.