Team preview of the Boston Celtics ahead of the 2026-2027 NBA season. Last NBA season: 58-26, lost to Philadelphia in first round of playoffs. Coach: Joe Mazzulla (5th season, 238-90). Season opener: Oct. 20 at Detroit. Departures: F Jaylen Brown, C Nikola Vucevic, F Anfernee Simons. Additions: F Paul George, C Mitchell Robinson, G Mike