NBA: Miami Heat at Boston Celtics
Daniel Theis will be losing the mask for the London game against the Philadelphia 76ers. Photo: Greg M. Cooper-USA TODAY Sports

Per Adrian Wojnarowski of the ESPN, the Boston Celtics have extended their qualifying offer to Daniel Theis.

Consequently, the German center will become a restricted free agent when free agency starts (June 30).

The Celtics can match any offer made to Theis by another NBA team during the free agency in order to keep him in the roster.

Theis averaged 5.7 points, 3.4 rebounds and 1.0 assists in 66 regular season games with Boston in the 2018/2019 season.