This is simply because some of the players that he meets regularly during the later rounds of tournaments have figured him out. The obvious ones are Djokovic and Murray but now you can pencil in Berdych/ Del Potro and who knows how Nadal might play when he gets back (he could have another 2010). Maybe Tsonga can be added to this list. These players are playing with a high degree of confidence against him, there's nothing in Feder's arsenal that can hurt them too much now. All of them are much younger players at their primes. Fed is doing everything to plan the year ahead well, by tweaking his schedule and staying healthy. He is also playing at a decent level at the moment. He will still do well but 2013 will not be good, by his own high standards.