The Spanish federation has proposed a one-year ban for Contador, rather than the standard two-year penalty, after his positive clenbuterol test at last year's Tour.
Contador spokesman Jacinto Vidarte told The Associated Press that the federation accepted Contador's contention that the result was due to "unintentional ingestion" of the banned substance.
If the ban is adopted, Contador would be stripped of the Tour title, and miss this year's race.
Contador has until 9 Febryary to present further evidence, before the Spanish federation's disciplinary committee renders a final verdict.
That decision can then be appealed to the Court of Arbitration for Sport by Contador, the International Cycling Union or the World Anti-Doping Agency.
Contador has vowed to appeal any ban. The UCI and WADA are waiting for the final decision before commenting.
"I'm well, I'm motivated and focused on my work," Contador said from the Saxo Bank team training camp in Palma de Mallorca. "It's the most important thing right now. Regardless of what's going on around you, you've got to work. That's what brings you rewards in the future."
Contador, who contends that meat he ate on a rest day in July provided the minute trace of clenbuterol, was expected to speak on Friday at a news conference alongside Saxo Bank team boss Bjarne Riis.
Contador's case highlights a growing concern that the drug can also be consumed unwittingly from eating bad meat. While clenbuterol accelerates fat burning and muscle growth to make it an attractive sports performance enhancer and slimming drug, it is also on WADA's zero-tolerance list.
Contador's case isn't unique.
Italian cyclist Alessandro Colo received a one-year ban, after an Italian tribunal accepted his argument that bad meat caused his positive clenbuterol test. German table tennis player Dimitrij Ovtcharov also used the same defence after testing positive for the drug, but WADA is appealing the German body's decision not to sanction him.
If stripped of the 2010 Tour victory, the title would go to runner-up Andy Schleck of Luxembourg.
Contador would not only miss this year's Tour if the ban is upheld, he would miss out on participating in the Spanish Vuelta by only three days because the one-year ban would end on 23 August.
The ban would be retroactive to 24 August of last year - the day he was informed of the positive control.
While Contador also won Tour titles in 2007 and 2009, he was forced to sit out the Tour in 2006 and 2008 after his teams were implicated in doping cases.
The 28-year-old Spaniard is only the fifth cyclist to win Tour, Giro d'Italia and Vuelta titles in a career, and his stature as the greatest rider of his generation is in danger.
"The team has backed me a lot. You've got to think of it that way," Contador said of his Saxo Bank team. "Things are going well and I'm lucky to be here. I've never had such good preparation as I've had this year. Over the three days here, I've trained incredibly well. Whatever improvements we make are very important. Races are decided by a matter of seconds."