That would be their new touring drummer, Arin Ilejay.  Dude used to be in a christian rock group called Confide.

Right before their first show of the Nightmare After Christmas tour last night in Pennsylvania, Avenged Sevenfold announced that Ilejay would be their touring drummer for the first part of this year.  We'll see if they keep him on.

I don't know why they didn't just keep Mike Portnoy from Dream Theater on, that guy's a fricken' animal.  This Ilejay dude must be pretty badass though.