"It's done," DeRozan said. "There's no reason to have a relationship"
Toronto sent DeRozan, Jakob Poeltl and a protected 2019 first-round pick to the Spurs for Kawhi Leonard and Danny Green on July 18.
Per ESPN.com's Chris Haynes, DeRozan came away from a meeting with Raptors officials during the summer league in Las Vegas under the impression he wouldn't be traded.
Ujiri told reporters after the deal became official there was a "miscommunication" with DeRozan during their meeting.
"We spoke ... I think maybe my mistake was talking about what we expected going forward from him," Ujiri said. "So, not necessarily talking about a trade but what I expect from him going forward, and I think that's where the gap was."
DeRozan spent the first nine seasons of his career with the Raptors, who selected him ninth overall in the 2009 draft. He signed a five-year max extension in July 2016.