Heinrich Haussler was forced to pull out on stage 4 of Paris-Nice after 35 kilometres of racing. Suffering from an injury to his left knee for the past two days, the Cervélo rider opted for retirement in order to protect his body before the Classics.
"He was scared that the injury would become worse," said Cervélo's directeur sportif Philippe Mauduit.
"His muscular sensations were extraordinary but the cold brings the pain back."
Haussler looked in top condition earlier in the season at the Tour of Qatar, although he didn't win the stage he desperately aimed for in the Middle East.
He crashed at the Volta ao Algarve and missed six days of riding his bike because of his sore knee.
"He was feeling good at the Belgian races one week before Paris-Nice [he came 2nd in the Het Nieuwsblad behind Juan Antonio Flecha] but he crashed again here with Alberto Contador and the pain bounced back."
Haussler will remain with his team until the end of Paris-Nice to receive treatment by doctors and physiotherapists.