It's been confirmed that a new character, Roy Stark, is heading our way in Season 4. Just in case you haven't checked out his page, all we know is that "he was a former army medic in the Military who is haunted by his past. He is lonely and self-depreciating but puts on a confident face for the public, while his self-deprecating public persona masks some seriously major personal demons".
The article said he will be a regular, but I doubt they would introduce a new character immediatly as a series regular so he will likely be a recurring character. Also based from his description, some people have theorized he will be the counterpart of either Abraham, or Bob Stookey. I think that Stark will be one of the Woodbury characters that moved to the Prison. Then again, it's also possibly that Stark is a leader of a group that gets recruited by The Governor to take out the Prison.
I think it would be interesting if we saw elements of Post-Prison characters in the Woodbury defects. I also think that Stokes will be in the Prison, but once again just another theory :D
In terms of appearance, I think it would be natural to assume Stark is an older man based on the fact that he didn't participate in the assaults. Or maybe Roy isn't even from Woodbury, and Rick finds his character somewhere else. Anyways guys, sound off below with your speculations and theories!
Also speaking of Woodbury defects, it would also really be cool to see Robbie at the Prison helping the group manage their food (planting crops with Hershel and his family, aiding Glenn in supply runs, and possibly even farming animal).