I don't know... He probably looked at the competition from last year (Sastre, Evans, Menchov, Vande Velde, F.Schleck; to name the un-convicted top-5) and said to himself that he could beat those guys. And to be fair to him, he finished higher up than all of last years' returning top 10, so he might've had a point. And just how dominant had Contador shown himself when LA announced his return? He'd done v. well in some shorter stage races, but he won the '07 Tour by a tiny margin, won the '08 Giro with good time-trialing but no dominant climbing performances, and the '08 Vuelta with less than a minute over Levi Leipheimer. LA simply fancied his chances I'd say.