Tillman agreed to a two-year deal with the Celtics on Tuesday, Adrian Wojnarowski of ESPN reports.
Tillman stepped up in Kristaps Porzingis' (foot) absence throughout the 2023-24 NBA Playoffs, and the former will return to the club as it aims to repeat the success from last year. The Celtics acquired Tillman via trade with the Grizzlies on Feb. 7, and he went on to average 4.0 points, 2.7 rebounds and 1.0 assists across 13.7 minutes in 20 regular-season appearances with Boston.