Blake, 34, agreed to take the Blazers' biannual exception, sources said.
This will be Blake's third stay with the Blazers. He spent the 2005-06 season in Portland and played another 2½ seasons with the Trail Blazers from 2007-10. The Los Angeles Lakers traded Blake to the Golden State Warriors at the February deadline, where he became a free agent this summer.
Blake has averaged 6.9 points and four assists in his 11 NBA seasons.