Agree with other posters, Delpo is No.1 candidate for slam final, but i honestly think it won´t be in 2013.
His best chance would be at RG with good draw, but his chances in QF vs big 4 are like this
vs Andy - clear favorite
vs Roger - 50-50 match
vs Nole - underdog
vs Rafa - clear underdog
so if he beats someone there is still another one in SF.. - even Ferrer can take him down at RG in SF - if Ferrer beats Murray in QF.
At AO - i don´t like his chances vs big 4 at the beginning of the season when all are fresh and full of energy + his stamina on slow HC in heat - his draw must be joke if he makes F alredy in Melbourne
Wimbledon - no way
USO - 2nd best chance after RG, but everyone can play good at HC - no matter how fast or slow USO will be , Nole-Andy would be favorites vs him, even Rafa can be tough and well Roger still can beat him at HC too.
I have to disagree, if in the latter stages Del Potro meets Murray in RG, I think Murray will clinch it, Delpo will fold. He is the underdog against Federer too. When Federer started to play (not even play well) in RG 2012, the match was over, Del Potro couldnt move.
The chance he will get is in the USOpen, provided he has a good draw. Basically, he is a good hard court player, nothing more than that, I dont understand how people choose to ignore the fact that he isnt good enough on slow courts...