Australian Olympic swimmer Ian Thorpe is being treated in hospital for a severe infection in his shoulder.
Media reports suggest there are fears he may lose the use of his arm.
His agent, James Erskine, said the former Olympic champion is "quite sick" and he will never swim again competitively.
However, Erskine dismissed reports that Thorpe would lose the use of his arm.
It's serious but it's not life-threatening," Erskine said. "He's contracted two forms of bugs in hospital.
"He's undergone two or three operations over the last two months so ... I mean bad luck.
"He's quite sick but that's the situation."
The ABC reports it was Thorpe's third shoulder operation. He was also admitted to a rehabilitation clinic in early February.
Thorpe was found disoriented near the home of his parents in Sydney after taking a combination of anti-depressants and medication for a shoulder injury.
Thorpe, 31, made his Olympic debut in the Sydney games in 2000 where he won three golds.
He won another two in Athens 2004 before retiring in 2006.
He made a comeback in 2011 but did not make the Australian team for London the following year.