Quote Originally Posted by fire_of_avalon View Post
Daryl has never met Morgan, guys. I am sure he knows of him but not enough to invite him back to camp. Remember, the last time Rick, Carl and Michonne saw Morgan he was nuts.
I'm guessing Daryl and Carol ran into Morgan somehow in connection with Beth or her captors. Morgan mentions he's looking for a guy named Rick, and explains some of their background. Daryl is wary but thinks it might be okay to bring him back, especially if he maybe has information about Beth. Carol stays behind to keep an eye on the Beth-captors.

Morgan was nuts, but he didn't seem nuts in the post-credit scene after episode 5.1, and definitely seemed to be looking for Rick, or at least other people. It is possible for people to come back from losing their minds. He was temporarily insane, but there was nothing to indicate it was permanent.