Johannesburg - Ralf Naef, one of the contenders for the men's overall title at the Cape Epic, and England's Catherine Williamson have withdrawn from the race with injuries, race organisers said on Wednesday.
The eight-day, 718km race starts with a prologue at Meerendal Wine Estate, Durbanville, on March 23.
Switzerland's Naef, previously a top 10 Cape Epic finisher and one of the world's top riders, was scheduled to partner countryman Lukas Flckiger in Team BMC.
Flckiger will now partner with rising star Martin Fanger, who is also Swiss.
BMC said in a statement that Naef "sustained an injury to his quadriceps a few weeks ago during training, and it has turned out to be more severe than anticipated".
Williamson - winner of the women's category with Yolande Speedy last year -- was a favourite for the mixed category, and misses out after breaking her leg in a skiing accident.
She was to ride with South African Nizaam Essa (Team Asrin). He will instead partner with Austrian marathon champion Christina Kollman.
He will meet Kollman for the first time when she arrives in Cape Town five days before the Epic.
However, Essa is determined the pair can challenge for the top step of the podium when the race finishes at Lourensford Wine Estate, Somerset West, on March 30.