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.
Premier League newboys Cardiff are set to complete their first summer signing with the acquisition of striker Andreas Cornelius from FC Copenhagen for an undisclosed fee.
The 20-year-old made a big impression during his first full season in the Danish Superliga, racking up an impressive tally of 18 goals from 32 appearances and appearing for the full national side.
The deal to bring him to Cardiff City Stadium will be completed once he passes his medical.
A statement on the Cardiff website said: "Cardiff City Football Club have today reached an agreement with F.C. Copenhagen for the services of Andreas Cornelius, the 20-year-old striker is set to join the club for an undisclosed fee on completion of his medical."
Cornelius has made the decision to move to the Premier League despite having the chance to feature in the Champions League with Copenhagen after his goals helped fire them to the Danish title.
Everton and Stoke were also reportedly interested in a move for Cornelius, but he has instead opted to join the newly-promoted Bluebirds.
Owner Tan Sri Vincent Tan had pledged to back manager Malky Mackay in the transfer market, and it is understood a club-record fee of over £8million has been spent on acquiring Cornelius' services.
A striker was always likely to be high on Mackay's wishlist after veteran Heidar Helguson topscored with just eight goals during their Championship-winning campaign.
Cardiff are also chasing Celtic's Victor Wanyama and Blackpool's Tom Ince, while there is also reportedly interest in West Brom's Peter Odemwingie and Reading and Wales winger Hal Robson-Kanu.