The former Rangers player joined the Dons from Motherwell on a two-and-a-half-year deal last January that would have kept him at the club until the summer of 2014.
But the 30-year-old is now free to discuss a move elsewhere after new Pittodrie manager Derek McInnes deemed him surplus to requirements.
An Aberdeen spokesman said: "The club can confirm that Stephen Hughes has been released from his contract with the Dons and is free to sign for another club.
"Everyone at Aberdeen wishes Stephen all the very best in his future career."
Hughes made 27 appearances for the Dons last season but is the eighth player to be culled from McInnes' group already this summer.
The former St Johnstone and Bristol City boss has already released seven out-of-contract players on top of telling Hughes and Jordon Brown to find new clubs.
Brown was handed a deal until 2015 by former manager and namesake Craig Brown last October but his successor has told the 20-year-old, who spent the second half of last season on loan at Forfar, he is also not part of his plans.
A severance agreement with the Reds youth team graduate has still to be reached but Rory Fallon, Mitch Megginson, Rob Milsom, Gary Naysmith, Isaac Osbourne, Gavin Rae - who has joined Dundee - and Dan Twardzik have all left Pittodrie after the expiration of their contracts.
McInnes has moved to bolster his squad, however, with the capture of former Celtic midfielders Willo Flood and Barry Robson.