Dude! That was Morgan.
Appeared in only two previous episodes, but super popular with the Walking Dead fans. He was the first adult human that Rick encountered after coming out of his coma in the very first episode. He was the one who educated Rick about what became of the World. In a later episode (much later) Morgan lost his mind after seeing his son bitten by his Zombie wife and son's mother because Morgan couldn't bring himself to put a bullet in her skull. And also because, after a short while, Rick broke his initial promise to Morgan to stay in touch via Walkie-Talkies at a certain hour every night.