The newspaper reported that the 25-year-old Villanueva was released by Halton Regional Police on a promise to appear in court on July 9. The name of complainant and other details about the incident weren't available Tuesday.
His lawyer, Owen Wigderson, told the Toronto Star that Villanueva, "denies all allegations of wrongdoing and I'm very confident that he'll be exonerated."
Villanueva has played five NBA seasons with three teams since being drafted in the first round by the Toronto Raptors. Last season was his first with Detroit. He signed with the Pistons as a free agent after three seasons with Milwaukee.