Manchester City have confirmed that Danny Mills, Darius Vassell, Dietmar Hamann and Michael Ball have all been released.
The quartet were not offered new contracts by manager Mark Hughes after falling down the pecking order at Eastlands and are now free to take up other offers.
Mills has not been part of the first-team for more than 12 months, while last season Vassell and Hamann both struggled for fitness.
Michael Ball was a regular for the start of the last campaign, but the former Everton player lost his place following the arrival of Wayne Bridge.
Vassell has been linked with a move to Turkey and is holding talks with Ankaragucu ahead of possible switch to the Super Lig side.