Former Manchester United and Ajax goalkeeper Edwin van der Sar is being treated in intensive care after suffering a bleed on his brain.
The 52-year-old is reportedly being treated in a hospital in Croatia, where he has been on holiday.
Ajax said the former Netherlands international, who won 130 caps for his country, 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 resigned from his role as Ajax chief executive in May after the side finished third in the Dutch league and failed to qualify for the Champions League for the first time since 2009.
He retired from playing after leaving United in 2011 before joining the Ajax board in 2012, and later becoming the club’s chief executive in 2016.
Van der Sar made 266 appearances for the Red Devils and helped them to win four Premier League titles and the 2008 Champions League.
In a statement, Manchester United said: “Sending all our love and strength to you, Edwin.”
He also played in the Premier League for Fulham and in Serie A for Juventus.
Former United defender Rio Ferdinand sent his support to his old team-mate, tweeting: “Ed is a fighter. Our thoughts are with the Van Der Sar family!”
Fulham also sent a message of support, tweeting: “Everyone at Fulham Football Club wishes Edwin a speedy recovery. We’re thinking of you.”
The Professional Footballers’ Association tweeted: “The thoughts of everyone at the PFA are with Edwin and his family.”
Simon Stone, BBC Sport’s senior football reporter
Football is united in hoping Van der Sar makes a full recovery.
First as a superb goalkeeper, with Ajax, Juventus, Fulham and Manchester United, plus the Dutch national team, then as an administrator, at Ajax and with the influential European Clubs’ Association, he has developed a first-rate reputation.
I spoke to him in Istanbul, on the day of last month’s Champions League final, when he talked about Andre Onana’s likely influence on the game, Erik ten Hag’s time at Manchester United and also his future plans.
Van der Sar endured a difficult final season with Ajax but, despite leaving the club, gave the impression of someone not intent on staying out of the game long.
Through the recovery of his wife Annemarie, who suffered a brain haemorrhage when he was a player at United in 2009 and Sir Alex Ferguson, who collapsed in 2018, there are positive examples to reflect on in this uncertain time.
Football is worried on Van der Sar’s behalf. There are many good wishes being extended in public and private as it absorbs this news.