if they fail to win the French Open title? Nadal or Djokovic? Assuming Nadal doesn't win: - He'll probably be more likely to have his first slamless year since 2005 if he fails to live up to his clay season expectations. In 2009, he had the AO title but was a non-factor at Wimbledon and the USO. - He is unpredictable for Wimbledon so I wouldn't favour his chances much and the USO will require him to be on very good hardcourt form (e.g. 2010 and 2013 repeat) or else, he'll be clobbered by Djokovic/Murray. Assuming Djokovic doesn't win: - I can still see him having chances at Wimbledon and the USO since he consistently makes it deep into those slams in recent years. But usually, he bows out to a more superior grass court player like Federer or Murray in the late stages so winning the title will be a big ask. And his poor record in USO finals is a concern as well. - All in all, he seems more 'consistent' at making deep runs at every slam so I'd give him a less chance of being slamless for the year (assuming he doesn't win RG and will need to win Wimby or USO). Assuming none of them win (very low chances of this happening): - Same points apply to Djokovic and Nadal. If none of them captures the RG crown, it means they'll have to both split the Wimby and USO duo in order to ensure both are not slamless for the year. - Contenders for the RG crown are little though so... I mean Federer is the only other player who realistically has a tiny chance - given he has a good day against Novak in the latter stages and Rafa has been upset in the earlier rounds. Murray is unpredictable on clay, Berdych is unpredictable in terms of his form between rounds and Wawrinka has been slowing down.