The deal is for the veteran's minimum, the sources said. Golden State now has 15 guaranteed contracts, making their roster complete.
The Warriors invited McGee to training camp last summer, and he made the 15-man roster as a veteran rim protector.
The 7-footer ended up appearing in 77 games, averaging 6.1 points, 3.1 rebounds and close to 1.0 blocks per game.
Prior to Golden State, the 29-year-old McGee enjoyed stints in Washington, Denver, Philadelphia and Dallas. He holds career averages of 7.8 points 5.0 rebounds and 1.6 blocks.