Lorient - Australia's Michael Matthews pulled out of the Tour de France prior to the race's fifth stage due to sickness, according to his Sunweb team.
Matthews won the points competition's green jersey in 2017.
But the 27-year-old Canberran's hopes of challenging for the prize again came to an end prior to the start of Wednesday's fifth stage from Lorient to Quimper.
"We're sad to report that @blingmatthews is unable to start #TDF2018 this morning due to sickness. Feel better soon, Michael!," said a statement by Matthews' Sunweb team.
Matthews won his maiden Tour de France stage in 2016, taking his tally to three from two editions when he won stages 14 and 16 a year later.
In 2017 Matthews also won the race's green jersey, but only after sprint rivals Mark Cavendish, due to injury, and Peter Sagan, who was disqualified, were forced off the race.
Sagan, who rides for Bora, had won the green jersey the five previous editions (2012-2016) and was wearing it at the start of the fifth stage to Quimper.