The former Australia captain and 1991 rugby World Cup winner Michael Lynagh is in a Brisbane hospital after suffering a stroke from apparent blood clots in his brain.
The 48-year-old Lynagh was admitted on Monday after becoming ill while visiting the Queensland capital.
The former Australian captain Andrew Slack says Lynagh had been experiencing vision problems in one eye but doctors were not certain what was the cause.
He says Lynagh is in intensive care as doctors try to work out precisely what he's suffering from.
Lynagh retired from international rugby in 1995 and moved to London where he played club rugby for Saracens.
He has remained in Britain since he ended his playing career.