Former Swansea City midfielder Ferrie Bodde is in an induced coma after being diagnosed with pneumonia.
Bodde, 31, is head coach of Dutch amateur club SV Wateringse Veld.
In a statement, the club said Bodde was in hospital, adding: "It was decided to keep Ferrie in an artificial sleep for a number of days to fight the bacterial infection and to prevent damage to the organs.
"We are obviously very shocked by this news and wish him a speedy recovery."
Bodde joined the Swans under then-manager Roberto Martinez in June 2007 from ADO Den Haag and left in July 2012.
He suffered three cruciate knee ligament injuries during his time at Liberty Stadium.
Between November 2008 and his departure, Bodde played only four first-team games for the Swans.
As he left the club, chairman Huw Jenkins said of the player: "He would have been one of the best players in the Championship and probably one of the best in the Premier League barring the injuries."
Bodde had joined the club for an initial £50,000 in 2007 and proved a bargain.
His displays attracted interest from Derby County, Middlesbrough and Reading, while in subsequent seasons Swansea had to fend off bids from Wigan Athletic and Bolton Wanderers.
After leaving the Swans, he attempted in vain to resurrect his career at Wigan and Den Haag.