Australian gold medal favorite Jacqui Cooper injured her right knee in practice on Monday and will not be able to compete in women's aerials this weekend.
The 29-year-old three-time World Champion represented Australia's best chance at its first gold medal. She is currently ranked second in the world after struggling with a sore back most of the season.
Cooper fell backward on her last jump of the day doing a triple flip and hit the snow with her right leg turned awkwardly outward. She told doctors she felt something, "like a little explosion inside my knee."
She was examined at Deer Valley where the aerials qualification round is scheduled to begin Saturday. Then she was taken by ambulance to the Olympic Village in Salt Lake City where she underwent an MRI.
"Initially I thought there was perhaps a glimmer of hope that she might be able to do something here, but with those MRI results, it's now obvious she will not be able to train or compete," said Australian team doctor Peter Braun.
Cooper is the only woman to win three World Championships in a row and was among the first to execute a triple flip in competition. She's had unfortunate luck in Olympic Competition and injured herself in the 1998 Winter Games in Nagano, where she finished 23rd overall.