SWIMMING: Ian Thorpe's manager says Australia’s greatest Olympian was unlucky to have contracted a serious infection that's laid him up in hospital.

Thorpe is receiving treatment in a Sydney hospital for the infection contracted after undergoing a series of surgeries on his shoulder at a hospital near his home in the Swiss town of Ronco Sopra Ascona.

"He's under very good supervision and he's battling and he's unlucky," Mr Erskine said.

"How long it's going to take to clear up, I don't know. He's battling it out in hospital ... he's a sick boy."

Erskine said Thorpe is not in intensive care but remains sick. Considering his serious condition he is in good spirits and has been visited by family and friends.

The swimmer who won five gold, three silver and 1 bronze from the Sydney 2000 and Athens 2004 Olympics attempted a comeback ahead of the London 2012. His manager has said it is unlikely that the former world champion and world record holder will ever swim competitively again.

Thorpe's father revealed in February the Olympian was battling depression.

He sought help early this year after being found disoriented near his parents' Sydney home after taking a combination of antidepressants and medication for a shoulder injury.

Thorpe was sent for a medical assessment at Bankstown Hospital and then entered a rehabilitation program.

The Olympic and swimming fraternities all around the world are wishing Thorpe a speedy recovery.

AOC and AAP