nishikori just has bad luck with injuries.
just look at hewitt. he has had his share of them in the last few years. nalFATian also has had his bouts with injuries.
nadal makes his own injuries so i have no sympathy for him.
For Nishikori you won't know how it will be for his career.
I don't share that opinion about Bandy and Hewitt though. Nalbandian never lived entirely for the sport, and talent alone doesn't get you that far. People think Fed also has a lousy work ethic but they are mistaken.
Hewitt could be a top contender during the transition years, and he got there pure by his iron will and dedication. He just doesn't have any real weapons to hurt the top guys with and that's a fact. Yes he has been unlucky with injuries but that guy is a big big overachiever thanks to his won't quit mentality and I respect him for that.
As for Nadal. He just needs to take a look at Fed's scheduling book and maybe then he will be a little wiser. Nadal wanted to go for the history books so he evolved as a player playing on HC (which is bad for his knees). Now he does have 2 HC slams and not the stamp of being only a Claycourt specialist but on the other hand he also has f**ked up knees now.