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.
Palermo president Maurizio Zamparini insists Federico Balzaretti will remain in Sicily next season despite the defender attracting attention from Serie A's top clubs.
The Italian left-back enjoyed another solid campaign for the islanders and is a reported target of Napoli, AC Milan and Lazio this summer.
"Balzaretti will not leave," Zamparini said to Gazzetta dello Sport. "He will remain at Palermo."
Palermo are expected to offer Balzaretti a contract extension with the player's current deal ending next summer.
The 30-year-old is currently on international duty with Italy at the European Championship in Poland and Ukraine.