This could also be Tor-An, a large Kryptonian played by stuntman Richard Cetrone. He can be seen without his helmet in a couple of scenes, and is a fairly tall guy (6'4"). If it IS Cetrone, obviously his height was enhanced with CGI in post-production.
Here is his first appearance, when Zod lands on Jor-El's landing pad during the Krypton battle. That's him in the center background:
He can be seen again briefly when Zod is exploring the Kryptonian colony world:
Cetrone is probably known to most genre fans as "Pierce" in the Underworld franchise. He was also the stunt-double for Tony Stark in Iron Man, as well as the stunt double for Ben Affleck in the upcoming "Batman vs. Superman: Dawn of Justice". While looking this up, I learned he was also the lead antagonist (Big Daddy Mars) in "Ghosts of Mars" as well as the Merman (AND the Werewolf) in "Cabin in the Woods". So even if the big guy isn't Tor-An, it may still be Cetrone doing the motion capture work for the character.