Cardiff will allow long-serving Kevin McNaughton to leave this summer along with Danny Gabbidon and Nicky Maynard.
Highly-rated Atletico Madrid midfielder Saul Niguez has signed a new five-year contract.
Sunderland boss Martin O'Neill is ready to block Hull's move for Fraizer Campbell by keeping the striker at the Stadium of Light.
Hull chief Steve Bruce is keen to sign Campbell when the transfer window reopens in January as he looks to boost his side's promotion bid from the Championship.
Bruce is a big fan of Campbell having signed the 25-year-old when he was in charge of Sunderland and he has admitted he would like to sign the former Manchester United youngster.
"I like Fraizer both as a player and a boy. If anything was possible, we'd certainly look at it," said Bruce.
However, O'Neill insists he is in no rush to sell Campbell after seeing his score in last weekend's defeat to Manchester United.
"Fraizer did really fine for us against United," said O'Neill. We will need him around here between now and New Year for a start.
"I would say we want to try to strengthen the squad if at all possible rather than let players go."