Tour de France winner Egan Bernal will not ride in the Road World Championships in England on 29 September.
Bernal has pulled out of the Colombia team for the race in Harrogate and has been replaced by Carlos Betancur.
The 22-year-old beat Britain's Geraint Thomas to become the first Colombian to win the Tour de France in July.
"The talented Team Ineos cyclist decided to turn down the call-up," said the Colombian Cycling Federation.
Bernal tweeted on 4 September that he would not compete in Yorkshire if he did not feel he could perform at his best wearing his national colours.
The 285km course being used for the road race is not especially hilly and may not have suited a mountain climber like Bernal.
Bernal became the youngest winner of cycling's most famous event for 110 years when he claimed the Tour de France in the summer.