Leonard, who is out for the remainder of the season because of shoulder surgery in February, never joined the Thunder organization following the trade with the deal only being completed on paper to match salaries to move Ariza and acquire a pick.
The Thunder held onto Leonard through the trade deadline in case his contract could be used in another salary-matching trade. After the deadline passed, with the Thunder adding two more players which put them over the roster limit, Leonard was waived.
Leonard's NBA future is in doubt after he used an anti-Semitic slur on a video game stream, for which he was fined $50,000 by the NBA. Since his comments on March 8, Leonard has been working with the Jewish community in South Florida and will continue rehabilitating his shoulder and training in the area, a source told ESPN's Adrian Wojnarowski.
The 29-year-old center only appeared in three games this season for the Heat, but averaged 6.1 points and 5.1 rebounds last season for Miami.