The two Grand Tour champions cast doubt upon their participation in a press conference before the Tour of Britain, and on Wednesday, Team Sky directeur sportif Brett Lancaster confirmed the decision had been made for both riders to end their seasons after their home Tour.
"Froome and G [Thomas] will finish their seasons here, it's good to finish, on not necessarily a form wise high, but on a morale and psychological boost for next year on a high," Lancaster told Cycling Weekly.
"I think G originally thought about it [racing at Worlds], I would have wanted him there in the team time trial but obviously he is burnt out after a massive season and the stress they put themselves under with training and diet etc."
Both riders were listed on British Cycling's long-list for the national team events, but have yet to officially inform the federation of their decision.
Froome centred his whole season around an attempt at winning both the Giro d'Italia and the Tour de France. He succeeded at the Giro d'Italia in May, then turned around and finished third behind Thomas and Tom Dumoulin at the Tour de France.
Thomas took the lead of the Tour de France on stage 11 and never lost the maillot jaune, adding his first Grand Tour victory to victories in the Critérium du Dauphiné and the British time trial championships this season, and a second place in the Volta ao Algarve in February and third in Tirreno-Adriatico in March.
The absence of the duo puts Dumoulin as the top contender for the individual time trial and leaves the road race wide open for a variety of climbers and roulers.