I got a better look at him, and I don't think he's wild. the wild pigeons always seem to have these beady little eyes, and are usualy a vived red or orange. They are also very quick, nervous, and skittish from what I've seen. He seems to have brownish red eyes and is quite calm for a new comer.
I suppose there could be some pain that's making him hesitate. Or he could just be a cautious bird. Usually if they can fly or walk without problems, there isn't any injuries there.
I keep looking at that picture, and even though it's small and just a back view, I think if it isn't a feral, then it may be a lost young roller.