London - Former Tour de France champion Geraint Thomas has pulled out of the men's time trial at the cycling world championships in Yorkshire, where huge crowds are expected over the next nine days.
An expert time triallist, Welshman Thomas was set to feature in Wednesday's run to Harrogate but will now focus on next Sunday's road race instead.
"I've tried to get back into shape after my post-Tour break, but unfortunately I don't feel in good enough shape to perform to my best," said Thomas, who has struggled to attain the fitness level that saw him win the 2018 Tour de France.
"So the decision was made with my coach and Matt Brammeier at British Cycling to skip the TT and commit to the team for the road race."
The 2019 season has been tough on Thomas, who suffered a nasty fall in Switzerland that skewed his Tour de France defence, leaving him to fight for fitness during the Tour, where he finished an impressive runner-up to his Ineos teammate Egan Bernal.
John Archibald, who will race Sunday's mixed gender team time trial, will now join reigning national champion Alex Dowsett in the 54km test against the clock.
GB's performance director Stephen Park said: "While it's a shame that Geraint is withdrawing from the time trial, we understand and support his decision.
"Geraint will still represent Great Britain in the road race. I have no doubt he will put in a performance that will do the team and the fans proud."
Thomas remains in the six-man GB team for Sunday's 285km road race from Leeds to Harrogate, along with Ben Swift, Owain Doull, Adam Yates, Ian Stannard and Tao Geoghegan Hart.