Swiss time-trial world champion Fabian Cancellara will have to ride the cycling road race on his own after his only teammate's Olympics came to a sudden end.
Michael Albasini fell during training in Beijing on Tuesday and suffered multiple fractures of his left collarbone, according to the Swiss Olympic team.
Albasini, 27, was to be flown back to Switzerland for an operation, the Olympic committee said. A replacement would not be named because there was not time for a rider to acclimatise before Saturday's race.
Cancellara is scheduled to compete in the road race on the first day of Olympic competition, but he is expected to be a bigger challenger in the individual time-trial.
Also, Swiss Olympic announced on Wednesday that wrestler Grégory Sarrasin would compete in the 66kg weight division.
Sarrasin just missed out on a place in qualification but was told he could take part after Hungary withdrew "for medical reasons".
Albasini's withdrawal and Sarrasin's participation leaves the Swiss squad at 84.