Well, he is like, Yeah, Canas played better. bluh bluh. But I mean come on man. This was the second round for the three times defending champ. I think Federer's dedication to Media and Tiger has affected his game a little bit. I think his game is shaky at best (He is good enough to win). I remember 2003-04 (Federer was always brilliant). Now it's like 2 points in every match. He won the AO, but he better win French or Wimbledon as a first/second/third round loss there would put Nadal in a striking distance.
Just out of interest: How long are you following tennis? Have you ever seen a player as dominant as Roger has been the last years? Even the most successful player of all time, Pete Sampras, had his losses once in a while and no one dared to say he should better concentrate on Wimbledon or the US Open.
And by the way: Nadal has also to defend a couple of points the upcoming months, it's not just Roger
Don't worry about Federer. I'm sure he knows best what went wrong in the match against Canas. He will be back