As was reported last month, the Celtics have agreed to a two-year deal with German forward Daniel Theis.

Adrian Wojnarowski of ESPN also reported the signing Saturday, the day NBA free agency officially began.

Theis, 25, 6-8, 243 pounds, a power forward/center, averaged 9.6 points and 4.6 rebounds for Brose Bamberg of Germany, while shooting 41 percent from 3-point range and 64.5 percent on two-point attempts. 

He has been an important contributor on a team that won three consecutive national titles in Germany in addition to the 2017 German National Cup.

With Amir Johnson, Jonas Jerebko and Tyler Zeller all not likely returning, the Celtics need to bolster their frontcourt. They lost out on All-Star Paul George, who was traded to the Thunder, and have targeted free agent Gordon Hayward.

Two Celtics big men, 2016 first-round picks Gershon Yabusele and Ante Zizic, spent last season playing overseas but are likely to be with the Celtics for this upcoming season. Zizic will play with the Celtics summer league team that opens Monday in Salt Lake City.