Hmm...Let me see.Fed has 5 USOpen,Nadal has 0.I'm guessing Fed and even Murray/Djokovic have and advantage over Nadal there.So yeah,Nadal was right,Fed is the favourite.
Wimbledon.Up until this year,Fed had 5,Nadal 1.I'm pretty sure that Fed is favourite so again Rafa is right.
AO.Fed has 3 and Rafa 1.Federer is favourite.
The only Slam in which he is favourite over Roger is the FO where he has 4 and Roger 1.Pre-emptive excuses? How is stating a reality an excuse? He will never be 100% again unless he takes something like 6 months off(or a big period of time),so he isn't entering USOpen in his best form.Nadal will never be a favourite at the USOpen because it is his worst surface,jut like Fed will never be a favourite at the clay of RG.How is Fed not a favourite at the USOpen? He has 5 there,Nadal doesn't even have a final.Nadal is not afraid to speak his mind.In 2006 I think he said something like "Fed is the best in the world,just not here",when speaking about Fed and RG so it's not like it is false modesty.The guy knows his place and realises that Roger is a big favourite outside of RG,especially at USOpen.
It is not Nadal's mentality to say he can win from the start.Even last year,when he pounded everyone at RG,he said he wants to take it step by step.It is something his uncle taught him,to see defeat as a real possibility and fight against it,fight to win.Nadal knows he can lose,that is why he doesn't make clear statements at the start of the tournament.He obviously also knows he can win but he knows he has to do it first and talk about it later.