I was just reading the thread on CM Punk's Heel Turn on the 1000th episode of RAW, and I thought to myself: If Rock's going to be at SummerSlam, Royal Rumble 2013, and Wrestlemania 29, and if he faces John Cena, can this be Cena's chance to turn heel?
If The Rock and Cena face each other, and Rock stays baby face, do you think Cena could turn heel?
Of course this is only CM Punk does not face the Rock (Assuming he might after what he did to Rock that turned him heel).
I personally think this could be Cena's chance to run free and wild as a heel, only because The Rock is a big enough star to carry the WWE as a face (merchandise, sales, tickets, etc.) through these PPVs.