The striker and defender Sam Ricketts, who has agreed a two-year deal, are the only players to commit to the club.
Negotiations with Jussi Jaaskelainen and Zat Knight are ongoing.
Ricardo Gardner, Gretar Steinsson and Ivan Klasnic are among those released, while Nigel Reo-Coker has activated a release clause in his contract.
Paul Robinson, Sean Davis, Robbie Blake, Mark Connolly, Tope Obadeyi, Rhys Bennett, Dino Fazlic and Tom Eckersley have also not been offered new deals.
Meanwhile, Tuncay, Ryo Miyachi and Dedryck Boyata have all returned to their parent clubs after reaching the end of their loan spells at the Reebok Stadium.