Celtics' Joe Mazzulla wins NBA Coach of the Year after leading Boston to unexpected 56-win season

Joe Mazzulla has won the NBA Coach of the Year award after guiding the Boston Celtics to a 56-win season and the Eastern Conference's No. 2 seed. The achievement is considered unexpected largely because the Celtics played most of the season without star forward Jayson Tatum. Mazzulla's ability to keep Boston competitive despite the absence of their key player was central to his recognition.