Ajax reveal Van der Sar remains stable but condition 'still concerning'
Van der Sar, who played for Ajax and then Manchester United, was on holiday on a Croatian island when he fell ill.
"Edwin van der Sar will remain in intensive care for the time being. His condition is stable but still concerning," Ajax said in a statement, adding that they were sharing the update on behalf of his wife Annemarie.
"The Van der Sar family, along with Ajax, is grateful and deeply touched by the many messages of support."
Van der Sar announced in May that he was quitting as Ajax's chief executive after the worst season in 14 years for the historic Dutch club, who finished third in the Eredivisie.
Regarded as one of the world's all-time best goalkeepers, the 130-times capped Van der Sar played for Ajax from 1990-1999, winning the Champions League in 1995.
He went on to lift the European Cup again in 2008 with Manchester United after spells at Juventus and Fulham.