Robinson, 23, spent most of last season in the G League with the Delaware Blue Coats. He averaged 5.5 points, 3.4 rebounds and 5.9 assists per game, shooting 40.5% from three-point range.
Robinson also signed two 10-day contracts with the Thunder toward the end of the season. He saw action in nine games, averaging 2.3 points and 9.8 minutes.
Milwaukee still has one open roster spot to use for training camp later this month. The franchise is coming off its first championship since 1971, bringing back much of the same core for the coming season.