World cycling chief Pat McQuaid admitted he would be "very disappointed" if it was proved that top rider Frank Schleck has been involved in doping.
But the president of the International Cycling Union said the UCI is powerless to stop the Luxembourger, who wore the Tour de France yellow jersey in July, from competing at the men's road race in Varese at the world championships on Sunday.
Schleck has been called to a hearing by the Duchy's anti-doping authorities over a report which claims he paid 7000 euros into a Swiss bank account held by Eufemiano Fuentes, a doctor at the centre of the 'Operacion Puerto' doping affair which erupted in Spain two years ago.
Over two years after revelations of a blood doping network run by Fuentes, the Spanish courts - despite the UCI receiving support from the World Anti Doping Agency (WADA) and the International Olympic Committee (IOC) - have effectively shelved the case.
McQuaid and the UCI led a futile bid to prevent another Operation Puerto suspect, Spanish ace Alejandro Valverde, from competing at last year's world championships in Stuttgart.
Speaking in Varese, the world cycling chief said: "Last year, when we believed we had evidence from the Puerto affair that would have stopped him from riding, we tried to stop him from racing the world championships.
"It was the decision of a judge that allowed him to compete. But at this moment in time we have nothing, no evidence against Frank Schleck."
He added, however: "I would be hugely disappointed if it was proved that Schleck turned out to be cheating."
German newspaper Suddeutsche Zeitung claims that Schleck, who rides for the CSC team, transferred the money in March 2006. It was in May of that year that police raided Fuentes' Madrid laboratory and uncovered doping products and blood bags.
While names of around 200 'clients' from the world of sport were reportedly found, only a few cyclists - including Italian star Ivan Basso, the former leader of Schleck's CSC team - were punished.
Confronted with the allegations, Schleck said late Friday: "I've done nothing illegal. I have not doped."
The UCI's anti-doping chief, Anne Gripper, said the UCI would apply the rules to the letter before deciding, once they have seen the necessary evidence, whether to open any disciplinary procedure.
"We have to make sure all the legal issues are counted before we even decide to open a disciplinary procedure against a rider. And those rules exist in all sports, not just cycling," she said. "We have to balance being firm and being fair, and we have to ensure the fairness is provided to the riders and athletes from all sports.
"There needs to be very strong evidence before we can even open a disciplinary procedure, and stop them riding. We will obviously seek the information that is alleged to be available. We'll get this as quickly as we can through the authorities."
Alleged links to Fuentes, which have never officially been proven, effectively prompted the retirement of former Tour de France winner Jan Ullrich of Germany.
Basso was snared by a codename on one of the blood bags, which was labelled with the name of his dog, 'Birillo'. Some have claimed that another blood bag, labelled 'friend of Birillo', relates to Frank Schleck.
© AFP 2008