Kieron Dyer started his career at Ipswich Town and won 33 England caps between 1999 and 2007Ipswich Town say their under-23 manager Kieron Dyer is "undertaking tests" in hospital.
The former England, Ipswich and Newcastle midfielder, 42, retired from playing in 2013 and has been in his role at Portman Road for a year.
Dyer suffered a collapsed lungexternal-link last month while appearing on reality show Celebrity SAS: Who Dares Wins.
"Everyone at Ipswich Town Football Club sends their best wishes to Kieron at this time," a statement said.external-link
"We ask everyone to respect Kieron's privacy, and we will be making no further comment on the matter."
