BMC Racing have confirmed that Richie Porte will not be able to take part in the Tirreno-Adriatico as he is suffering from an upper respiratory infection.
The Australian had been hoping to be involved in the race as he steps up his preparations for the Tour de France but illness means he will have to reappraise his future plans.
"Richie Porte developed an upper respiratory infection after Volta ao Algarve which forced him to miss the best part of a week's training,” said BMC Racing Team Chief Medical Officer Dr Max Testa.
"Given Tirreno-Adriatico was one of Richie's goal races this season, it did not make sense to line up when his preparation was far from ideal."
The BMC team will include former winner Greg Van Avermaet, the Italian climber Damiano Caruso and Australian Rohan Dennis.
Dennis, who is keen to do well at this year's Giro d'Italia, wore the leader's jersey at the recent Abu Dhabi Tour until fading in the closing stages.
He said: "I'm looking forward to going back to Tirreno-Adriatico. One main goal of the team will be to win the opening team time trial again, and we are motivated to do that.
"For me, the individual time trial will, of course, be another target and I hope to repeat my success from last year. In between the two, we will see what happens."
Meanwhile, Caleb Ewan is 33/1 to win the Milan-San Remo later this month and Van Avermaet can be backed at 25/1 to triumph.
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