Ben O'Connor (AG2R Citroën) was supposed to lead his team in this weekend's "Boucles Drôme Ardèche" - two Pro Series one-day races in the south of France, the Faun Ardèche and Drôme Classic, but will not race after contracting influenza.
O'Connor will not be replaced in the AG2R roster for the races.
The Australian would have been making his European season debut after an "unsatisfying" Tour Down Under, where he lost time on stage 3 and then missed out on a stage win on the last day.
Also out this weekend for Omloop Het Nieuwsblad is Dylan Teuns (Israel-Premier Tech). The Belgian came down with a severe cold and will be replaced by Guy Sagiv.
"The sinuses were already a bit inflamed since the Ruta del Sol, but in the night from Monday to Tuesday, everything broke through," Teuns said to Het Nieuwsblad.
"I didn't ride on Wednesday. I made an attempt today (Thursday, ed.), but it was unsuccessful. There's nothing else to do but sit out."
It is the second year in a row that Teuns' Classics campaign was interrupted by illness. Last spring, he missed Omloop Het Nieuwsblad after contracting COVID-19 but went on to win La Flèche Wallonne.
Without the weekend of racing, Teuns said he might alter his schedule.
"Basically, I had no races until the Tour de Catalunya, but maybe some races will be added now. First, get out and then full training again."
Jumbo-Visma confirmed that Sam Oomen fractured his shoulder blade in a crash at the Volta ao Algarve and will not be racing in Tirreno-Adriatico next week.
