Where has that been suggested?
Clearly he is "fit" in general terms. He wouldnt get a kick at all otherwise. But its all about levels and he clearly isnt fit enough as it stands.
Ryan Giggs is a great example - same playing weight as he was over 20 years ago, still has the legs to get through a game, albeit not every week.
Clearly he is a naturally fit and athletic person - but there is no doubt he makes a lot of sacrifices to maintain his fitness. He'll have changed his training and will certainly watch what he eats.
Here is a young lad who maybe hasnt had to put the graft in before, because his talent and youth have got him through. It's now patently obvious it wont get him through a game, and has been for some time. If I were him I'd be doing everything I could to get as fit as I could be.
Fact is, there is a clear problem for a Brazilian international in his mid 20's who cant get through 90 minutes. Be it injury or fitness - its largely irrelevant, it still makes him half the player he might have been.
What I dont get is people going head over heels into all sorts of weird and wonderful explanations and excuses. If it looks like a duck and quacks like a duck I'll assume its a duck. When someone is overweight and unfit it generally means he's not working hard enough.
I fully accept that he could be working harder but I just don't see that the club would be happy to let Anderson work at the levels people are making out and continue to play him on a regular basis while having such a fitness record.