LAUSANNE, Switzerland (AP) -- Alberto Contador has arrived at world sport's highest court for a hearing to decide if he doped when winning the 2010 Tour de France.
Contador did not speak with media gathered outside the Court of Arbitration for Sport before a scheduled four-day case.
The Spanish rider's lawyers will argue that a contaminated steak he ate on a rest day caused his positive tests for clenbuterol, a banned anabolic agent.
The International Cycling Union and World Anti-Doping Agency appealed to CAS after the Spanish cycling federation cleared Contador.
Around 20 witnesses are expected to give evidence, including the Spanish butcher who sold the steak, a polygraph expert and anti-doping scientists.
A verdict is expected in January.