The terms of the deal, which had been known for a week, don’t go into effect until the 2020-2021 season
The forward/center averaged a career-high 10.6 points, 5.3 rebound in 21.6 minutes over 77 games in 2018-19. That included 22 starts. He shot a career-high .597 from the field with a career-high of 26 points against Washington on March 6.
The Stanford ex was named one of 10 finalists for the NBA Cares Community Assist Award this season for his work in the community.
Powell, who is from Toronto, was acquired by Dallas along with Rajon Rondo in December 2014, in a trade that sent Jae Crowder, Brandan Wright, Jameer Nelson, a 2015 first-round pick and a 2016 second-round pick to the Boston Celtics.
He re-signed with the Mavericks in July 2016.