Paris (AFP) - Richie Porte on Saturday became the latest top rider to withdraw from next week's World Cycling Championships in Austria, the Australian citing a lack of training following a respiratory infection picked up on the Tour of Spain.
"I'm really disappointed to miss the road race," the 33-year-old said.
"It was a big goal for me at the end of the season and I had been training and racing with the road race in mind.
"However, recent illness means my preparation has been far from ideal and for a race of this difficulty, with more than 4,600 metres of climbing, you need to have the best preparation possible to be up there."
Porte added: "Within the Cycling Australia team, we have decided that it is in the team's best interests if my place goes to someone else. I wish the whole Aussie team the best and will be cheering them on from home."
Dr Max Testa, Porte's doctor with the BMC Racing Team, said the cyclist had developed an "upper respiratory infection towards the end of the Vuelta a Espana which has required him to take antibiotics and stop training".
"He will need a few more days off the bike to recover properly which means it does not make sense for him to line up at the Worlds Championships. Richie will resume training next week and will be able to race again this season."
The world championships will be held in Innsbruck between September 22-28, but missing alongside Porte will be the British duo of Geraint Thomas and Chris Froome, and Spain's Mikel Landa.
This season Porte won the Tour of Switzerland in June, but had to pull out of the Tour de France after crashing before rebounding at the Vuelta, when he finished 84th.