Former Newcastle goalkeeper Pavel Srnicek is in a critical condition in hospital after suffering cardiac arrest in the Czech Republic.
According to information received by his agent Steve Wraith, the 47-year-old collapsed while out jogging in Ostrava on Sunday.
"I spoke to his family in the Czech Republic who said his heart had stopped," Wraith told BBC Sport.
"He is in a critical condition in hospital and remains unconscious."
Srnicek became a fans' favourite during his first spell with the Magpies between 1991 and 1998. He was signed by manager Jim Smith and played under Ossie Ardiles, Kevin Keegan and latterly Kenny Dalglish.
While Keegan was in charge, Srnicek helped Newcastle win promotion to the top flight during the 1992-93 season.
He was also an integral part of the squad that came close to winning the Premier League title in the 1995-96 campaign.
Srnicek, who had spells at Sheffield Wednesday, Portsmouth and West Ham, was brought back to the club on a season-long deal in September 2006 as cover for the injured Shay Given.
He made 49 appearances for his country and was in Tyneside in December to promote his autobiography.