The move was made Tuesday before the team began minicamp.
The Vikings signed Mays as a free agent in March. He was a second-round draft pick out of USC by San Francisco in 2010 and traded by the 49ers the following year to Cincinnati, where he played three of his four seasons with the Bengals under defensive coordinator Mike Zimmer.
Zimmer has started his second year as head coach of the Vikings. Asked about the decision to let Mays go, Zimmer said only, ''It wasn't working out.''