Rumours of a possible comeback by seven-time Tour de France champion Lance Armstrong began circulating a couple of weeks ago, and have since been fanned by gossip at the Eurobike show in Germany and the Tour of Missouri.

However, is there any substance to these rumours?

An anonymous source first indicated to VeloNews that Armstrong would be ending his retirement to ride five races in the 2009 season: the Tour of California, Paris-Nice, the Tour de Georgia, the Dauphiné Libéré and finally the Tour de France.

According to the rumour, Armstrong is set to team up with his former manager at the Discovery Channel, Johan Bruyneel, who is currently running the Astana outfit. This sounds legitimate enough, and with rumours that the Texan is willing to ride completely without salary, it would be a perfectly orchestrated publicity stunt for the troubled team from Kazakhstan.

Further, USA Cycling has stated that Armstrong has not yet applied for a racing licence, but has not done this traditionally until the beginning of the season. Armstrong has also committed himself to out-of-competition testing from the American doping agency, in order to compete in the recent Leadville 100 mile mountain bike race (in which he finished second).

This brings us to the crux of the matter: what does the American possibly have to prove?

With seven Tour de France titles under his belt, Armstrong is one of the most successful cyclists in history. Standing on the podium on the Champs Elysées in 2005, Lance bowed out from the sport at his pinnacle. At nearly 37, age is certainly not on his side.

Armstrong was plagued by doping allegations throughout his career, and with the biological passport system now in place, it would be the ideal opportunity for him to prove to many that his career wins were based solely on hard training and commitment.

However, joining Astana would be unlikely to send out the right message. Last year, the team was dogged by doping scandals, forcing the squad to withdraw from the Tour de France in disgrace, after Alexander Vinokourov tested positive for blood doping. Team press officer, Philippe Maertens, was quick to reject rumours that Armstrong would be joining the Astana team.

Armstrong?s ambitions at the Tour de France would also be incompatible with Astana?s established Grand Tour contender, Alberto Contador. Further, four of the five races allegedly targeted by Lance are owned by ASO (ASO has a ?marketing agreement? with the Tour of California organisers), which took the step of banning the Astana team from its races this year, allegedly for past misdemeanours.

However, it is widely believed that it was in fact due to ASO?s falling out with Johan Bruyneel; if Armstrong were to join the team, it could well be detrimental to the team?s chances of selection to major races next year

Armstrong undoubtedly still has the competitive spirit, finishing two marathons within three hours since retiring.

However, if there is any grounding behind the rumours, and its not an elaborate marketing ploy from Astana/Trek/Armstrong/someone else, then Armstrong would have to sign for a team with a saintly image to stand any chance of being invited to the Tour de France.