Two-time Tour de France champion Alberto Contador, under contract with Astana until 2010, is unwilling to negotiate with his Kazakh-funded team until management issues are cleared up.
"Currently, we don't know who's leading Astana, that's why I have some doubts," Contador said of Astana, which has had financial troubles this season.
"That's my main problem, to know who is the manager, the official.
"In such a context you cannot negotiate and personally I don't want to sign up blindly with a team," said the winner of the 2009 and 2007 Tour of France.
"The situation must be cleared up, to see who'll head the team and what they propose, and it would be a good thing if there are guarantees, and the kind eye of the UCI and organisers of the main races."
Contador said rival teams Garmin, Caisse d'Epargne and Quick-Step had all been in touch should the Astana option fail.
Astana were created by and for disgraced Kazakh cyclist Alexandre Vinokourov, who was thrown out of the 2007 Tour de France for blood doping.
Having recently returned to competition Vinokourov wants to race for Astana again and has thrown his weight behind keeping Contador in the team.