My gut tells me he misjudged an out of season autologous blood doping after using clen.
And no doubt UCI/WADA felt exactly the same and that is why the samples were tested in the way they were tested and the reason why the case has been pursued. The role of plasticisers is also interesting as surely they get a feel for how much is normally present by drinking from plastic bottles or storing something in plastic containers. Equally, they would get a feel for such levels following transfusions etc. From other reports:
WADA's argument was that Contador had undertaken a blood transfusion of red blood cells on July 20, 2010 and then "in order to mask the use of such a transfusion... the next day injected plasma (to hide the variation of haemoglobin values)...into his system." CAS said "According to the appellants, it is the transfusion of plasma... which would have contaminated the sample with clenbuterol, resulting in the adverse analytical findings."
While he certainly made a remarkable comeback after his horrendous accident many years ago, some have questioned his performances and perhaps they were not expecting the level of testing that was undertaken in terms of the relatively very minute detection capability. I say ‘they’ as if the transfusion argument is true, then one assumes he did not do this himself.
Delgado and Indurain have been very vocal in protesting Contador's innocence, interestingly.
Ah yes, Indurain suddenly developed asthma as I recall, hence the reason why a banned substance was found in his body that was blamed on the sanctioned treatment for asthma.
I really do think they were clutching at straws with the steak explanation and a lot of people found that so unbelievable. Why some believe that someone cannot convince themselves they are innocent of any wrongdoing is equally unbelievable. I even think there is a medical term to describe such behaviour.