VARESE, Italy - The International Cycling Union (UCI) on Saturday raised doubts over whether Lance Armstrong will be legally allowed to compete at January's Tour Down Under in Australia.
Armstrong, the seven-time Tour de France winner, has targeted the first Pro Tour race of the season as his comeback race after a three-year absence from the road peloton.
However the UCI, world cycling's ruling body, said Armstrong would have to show that he has respected UCI's 'biological passport' rule demanding that athletes must be registered with an anti-doping programme six months prior to competing.
UCI chief Pat McQuaid, when pressed on Armstrong's intention to return as a professional in January, said: "The rules state that he must be in the anti-doping system within a six-month period.
"I don't know on what date Armstrong asked to be registered on the programme. But the UCI will apply these rules, regardless of the athlete."
If ruled out of the six-stage race, it will be a huge disappointment for the organisers, who have been bursting at the seams with excitement over the world famous Texan rider's aim to compete.
Armstrong announced this month his intention to try and secure an eighth yellow jersey by winning the 2009 Tour de France.
The 37-year-old American has joined the Astana team run by his former manager at US Postal and Discovery Channel, Johan Bruyneel.
However news of his return has received mixed reaction.
Armstrong has been accused of doping practices on several occasions, most notably in an article in French sports newspaper L'Equipe in 2005, claiming six urine samples from his 1999 Tour victory contained the blood-boosting drug EPO.
The rider himself has always denied doping and the UCI cleared him in 2006.
McQuaid said Saturday that whatever suspicions remain from the past, they were legally powerless to act against such reports.
"His (Armstrong) past is his past. And we have no possibility of proving anything he may have been accused of.
"We have had nothing, at any time, that would allow us to start a procedure against Lance Armstrong. And that's still the case, it seems."