Tonje will become a free agent after the Celtics declined to tender him a qualifying offer, Keith Smith of Spotrac.com reports.
Tonje was selected by the Jazz with the No. 53 overall pick in the 2025 NBA Draft, and he was traded to Boston in February. He spent the majority of the 2025-26 campaign playing in the G League, where he averaged 18.0 points, 4.3 rebounds and 1.6 assists in 30.6 minutes over 43 games between the Salt Lake City Stars and Maine Celtics.