Cena's "big match" losing streak continues as he's eliminated in the Rumble by Ryback or The Shield. Later, he costs Rock the WWE Title like Rock did to him at WrestleMania 27. At Elimination Chamber, Cena eliminates Punk but Rock pins Cena again to win the WWE Title. And there's how the rematch gets started. Punk can be included in a triple threat, or not but that's a much more interesting story and a more compelling rematch setting up situation.
Cena winning the Rumble is the obvious thing but the direct Cena-Rock build up would be far too long and would be a waste of the Rumble also promoting the World Title main-event situation.
Ryback or Ziggler are winning.