Cusset - Belgium's former world champion Philippe Gilbert pulled out of the Paris-Nice race on Wednesday suffering from a respiratory infection, his BMC team said.
"I really love this race so it is disappointing to have to stop racing," said the 33-year-old cyclist, who captured the world road race title in 2012.
"But I have one of my biggest goals for the season, Milan-San Remo, around the corner and in order to perform well there I need to fully recover from this illness and be in the best shape possible," added Gilbert.
"Phil's condition is nothing to be overly concerned about, however the cold weather and snow that we saw in the opening prologue and first two stages of the race have done nothing but aggravate his condition," team doctor Dario Spinelli reported.
Gilbert has yet to win the March 19 race in 12 attempts.
The multiple classics winner was placed 104th, 4mins 40sec behind Australian Michael Matthews, ahead of Wednesday's third stage start between Cusset and Beaujolais.