Reading pair Sean Morrison and Jordan Obita have both signed new contracts at the Madejski Stadium.
Ipswich defender Aaron Cresswell has signed a two-year extension to his contract.
Sunderland midfielder Cristian Riveros has completed a permanent move to Turkish club Kayserispor for an undisclosed fee.
The 29-year-old Paraguay international has spent the last season on loan in Turkey after failing to make an impact at the Stadium of Light, and has now severed his ties with the Black Cats.
Riveros, who was signed from Mexican outfit Cruz Azul by former boss Steve Bruce in May 2010, made just 14 appearances for the club.