Sanji will fight a Tobi Roppo or one of the Numbers..?? Are you kidding me... It has been made evident since the beginning of the story, that Sanji is first and foremost a cook, not a fighter. His skills as a fighter are abysmal, his talents belong mostly in the kitchen.
So no, he won't be fighting any of the above mentioned fighters. Infact, I think Luffy will make him sit this one out, like an extra on a sports team.