Full-back Clive Clarke has left Sunderland by mutual consent following concerns about his health.
Clarke made only four competitive appearances for Sunderland
He has not played a first-team game since collapsing at half-time in a Carling Cup tie at Nottingham Forest in August 2007 when on loan at Leicester.
Clarke, 28, was taken to hospital and fitted with a pacemaker.
A club statement said: "Clive Clarke has left the club following the termination of his contract by mutual agreement following medical advice."
The defender joined Sunderland from West Ham in August 2006 but failed to clinch a regular first-team place before being loaned to Coventry and then Leicester.
He began his career at Stoke, making more than 250 appearances for the Potters, and won one international cap for the Republic of Ireland.