The Spurs announced the move Thursday without disclosing terms.
Diaw played in 20 games, seven of them starts, after signing on with the Spurs on March 23. He averaged 4.7 points, 4.3 rebounds and 2.4 assists in 20.3 minutes while shooting .588 (40-68) from the field. In the playoffs, Diaw started all 14 games for the Spurs and averaged 6.2 points, 5.2 rebounds and 2.5 assists in 24.7 minutes.
The 6-8, 235-pound Diaw is a nine-year NBA veteran and a member of France's Olympic team with Spurs teammate Tony Parker.