The Tour de France organisers will refuse to let Chris Froome race in this year’s event if his salbutamol case has not been resolved, it is understood.

The four-times Tour champion returned an adverse finding for the asthma drug salbutamol during his winning ride at the Vuelta a España last year. He denies any wrongdoing and is continuing to race this season – as is his right under the World Anti-Doping Agency’s rules – while his team of lawyers and scientists work on an explanation for the adverse sample, which contained twice the allowed concentration of the drug.

The Team Sky rider confirmed on Wednesday that his final warm-up race for his first big target of the season, the Giro d’Italia, will be the Tour of the Alps, a five-day race in Austria and Italy that starts on 16 April. The Giro d’Italia organisers have said they are powerless to stop the 32-year-old Briton from riding in their race and the new UCI president, David Lappartient, has confirmed that Froome’s case will not be heard before the race starts on 4 May. But two senior cycling sources have stated that ASO, the French company that runs the Tour, has more discretion on whom it registers for its event and has no intention of letting a rider race with a potential anti-doping violation hanging over him.

ASO is understood to be confident that it could resist any legal challenge from Team Sky as it has clauses in its rules about safeguarding the image of the race. This would be a bitter blow for Froome, who is chasing a fourth successive victory in cycling’s most famous race and a record-equalling fifth win in total.

According to its rules, the UCI could also suspend Froome but Lappartient said at an event in Geneva on Wednesday that it did not want to do that. “It’s possible and it’s true that we have this power,” the Frenchman said. “But for salbutamol, it’s never been done, and we have to respect the rights of Chris Froome. It’s not possible to have a specific treatment for him.

“And no other international federation has taken this decision for salbutamol. So if we were the only international federation to do this - and just for one rider - I think we would be in the wrong and could badly lose if it went to [the court of arbitration for sport].”

Asked if the UCI would intervene to avoid the scenario of a race organiser having to make this choice, Lappartient said: “I think it’s the UCI’s job to deal with this matter – not the race organisers. But some of them are worrying about the consequences of this situation for their race and they wonder if they will have to try to refuse a rider. We hope that won’t happen and this is resolved quickly, so the organisers don’t have to do this. It’s not their job, it’s more a job for the UCI, Wada [the World Anti-Doping Agency], Cas and so on.”

ASO declined to comment on the specifics of Froome’s situation but said it hoped for a “fast outcome” to his case.

The 2018 Tour starts in France’s Vendee region on 7 July and finishes in Paris on 29 July.