America's five-time world figure skating champion Michelle Kwan has pulled out of the Winter Olympics because of a groin injury.
Kwan, 25, who has won silver and bronze at previous Olympics, was named in the US squad despite missing the national championships due to injury.
"Taking myself off the team is the most difficult decision I've ever made, but it's the right decision," said Kwan.
"I don't feel I can be at my best. I respect the Games too much to compete."
"Michelle means more to the US Olympic Committee than maybe any athlete that's ever performed for us"
Despite claiming nine US titles, Kwan has never tasted victory at the Games, and realistically this year would have been her final chance.
US Olympic Committee chairman Peter Ueberroth paid tribute to Kwan's honesty, and said she would be a loss to the whole team.
"She's made a courageous decision," he said.
"Michelle means more to the US Olympic Committee than maybe any athlete that's ever performed for us.
"She's been a leader, she's been gracious, she's somebody that cares for so many youngsters that are training in our country."
Her place in the squad will go to Emily Hughes, the third-placed finisher at last month's national championships, who is the sister of 2002 Olympic champion Sarah Hughes.
The 17-year-old will join the two skaters who beat her at the nationals, Sasha Cohen and Kimmie Meissner, in the US team for the competition, which starts on Tuesday.
Cohen said she shared Kwan's disappointment at being forced to withdraw.
"I'm a little bit shocked," she said.
"I know how tough it is to come back from an injury and get yourself together.
"It's great she tried, but things don't always work out."
Kwan said she would be returning home, rather than staying in Turin and being a distraction to her team-mates.
"It's physical pain that's keeping me from performing and skating," she said.
"But it's also emotional pain as well because I had to make this tough decision."