Cardiff City have released goalkeeper Tom Heaton and defenders Lee Naylor and Paul Quinn following their failure to gain promotion.
The three players arrived at the club during the reign of former Bluebirds boss Dave Jones.
Jones' present club Sheffield Wednesday are believed to be among the clubs interested in signing Heaton.
Cardiff were beaten by West Ham United in the Championship play-off semi-final.
The 26-year-old has played second fiddle to David Marshall this season although he featured prominently in Cardiff's Carling Cup run.
Former Wolves and Celtic defender Naylor joined Cardiff in August 2010 but his opportunities under Malky Mackay have been limited with Andrew Taylor preferred as left back.
Defender Quinn joined Cardiff from Motherwell for £300,000 in July 2009 and made over 50 appearances in his three years with the Bluebirds.
But the Scotsman played only five games for Cardiff during this season and his only Championship appearance came as a substitute against Southampton last September.
Meanwhile Cardiff have confirmed they will be travelling to Switzerland for a pre-season training camp.