Former Manchester United goalkeeper Edwin van der Sar is in intensive care in Croatia.
The 52 year-old is being treated for a bleed on the brain. He has been holidaying in Croatia with his family.
Van der Sar left Ajax as chief executive in May. He played for Ajax, Juventus, Manchester United and Fulham.
Ajax said the former goalkeeper, who won 130 caps for Holland, is in a "stable condition".
"Everyone at Ajax wishes Edwin a speedy recovery," the Eredivisie club added. "We're thinking of you."
Van der Sar won four Premier League titles and the 2008 Champions League.
In a statement, Manchester United said: "Sending all our love and strength to you, Edwin."