Spanish cyclist Alberto Contador went to sport's highest court Monday to argue his case that contaminated meat caused his positive drug test at the 2010 Tour de France. Contador did not speak to reporters as he arrived at the Court of Arbitration for Sport for a four-day hearing into one of the most scrutinized doping cases of recent years. Wearing a black suit and dark tie, he was accompanied by brother and manager Fran Contador and a team of elite sports lawyers. Contador's legal team will argue that a contaminated steak he ate on a rest day in the Pyrenees caused his positive test for clenbuterol, a banned anabolic agent. If found guilty of doping, Contador can expect to receive a two-year ban and be stripped of his 2010 Tour title and his 2011 Giro d'Italia victory. The International Cycling Union and World Anti-Doping Agency appealed to CAS after the Spanish cycling federation cleared Contador of blame last February. About 20 witnesses are expected to appear at the hearing, including the Spanish butcher who sold the steak, a polygraph expert and anti-doping scientists. The three-man arbitration panel, composed of Israeli chairman Efraim Barak, German law professor Ulrich Haas and Geneva-based lawyer Quentin Byrne-Sutton, is likely to issue its verdict in January. “A decision is not expected before the end of the year,” CAS secretary general Matthieu Reeb told reporters. The case opened in the CAS boardroom with Contador flanked by Andy Ramos, his Spanish lawyer, and Mike Morgan, an expert in sports doping cases from England.