Sydney, Jan 9 (DPA) Five-time Olympic gold medallist Ian Thorpe has started training again and has not ruled out being in Australia's 4x100 metres freestyle relay team at the 2012 Games in London, news reports said Sunday.

The 28-year-old retired in 2006 but is missing competitive swimming, the Sunday Telegraph reported.

Thorpe put on a lot of weight when he left swimming and began a university degree, but is back doing laps of the pool and getting into condition.

To be eligible to compete at the London Olympic trials in March 2012, Thorpe would have to inform governing body FINA soon.

"He hasn't put his name down to race again," David Flascas, Thorpe's manager, told the paper. "It will be nine months before he can race again after he puts his name down for drug testing."

Thorpe left the sport when illness and injury put him out of the Commonwealth Games in Melbourne.

Thorpe said he was enjoying swimming again. "I never really stopped swimming, I'm just doing more of it now and I'm really enjoying getting into shape," Thorpe said.

The 4x100 metres freestyle relay victory in Sydney, against a fancied American squad, was the high point of his career.

Michael Bohl, Stephanie Rice's coach, said last year that a Thorpe comeback would be a success. "He is one of the best freestylers I've ever seen. He has an absolutely perfect stroke," Bohl said.