Federer has announced today 9/11 that he'll play Davis Cup this weekend in Netherlands, and will arrive tomorrow. Obviously he waited for the results of yesterday's US Open before deciding as this is a very late commitment.
no no no he was officially in the team already tuesday 8 days ago and his presence had been confirmed in Swiss media two weeks ago, only in recent days he had put his presence in doubt, I don't know why, physical problem, Mirka or anything. He has other things in his life than watching the US Open final on TV
I'm also afraid that the whole fuss about the prize money in slams may take a lot of time and energy from him even though the ATP staff makes most of the hard work he has a lot to do for that especially to talk with the players, and the Aus Open has to announce the prize money for next year in a few weeks.
Anyway he was not expected to play any other Asian tournament than Shanghai, and if anything yesterday's result saves his chance for the year-end number 1 then would rather be an incentive NOT to play Davis cup to save energy to play more in the rest of the year.