Team Sky's Edvald Boasson Hagen could be a doubt for the Tour de France after falling ill.
The 24-year-old was named on Thursday in Team Sky's nine-man squad for the Tour, which begins this day week.
Reports from Norway suggest Boasson Hagen has contracted shingles, but a Team Sky spokesperson could not confirm the nature of the illness.
A Team Sky spokesperson said: "As a precautionary measure Edvald has withdrawn from the National Road Race Championships this weekend due to illness.
"We are monitoring the situation with him. At this stage there is no change to the Tour de France team."