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.
The 27-year-old has ended a four-year spell at the Bernabeu to move to Italy.
The Serie A club have plenty of money available to strengthen their squad following the sale of Edinson Cavani to Paris St Germain.
More to follow...