So in the comics theres a character called Allen and when searching the prison with rick and the group he gets bitten on the leg, so to stop him dying rick cuts allen's leg off. He doesn't become a zombie but he dies a while later from blood loss anyway.

Robert Kirkman said it will definitely happen to someone in Season 3 Episode 1 and Allen isn't in the show so who do you think it could happen to. In the trailer you can hear screaming and panicking and then the sound of a limb being chopped off, I think it could happen to either Hershel, T-Dog or Carol, but T-Dog's kind of unlikely.