Well, not quite "ruled out..."
”I think unless Superman’s power was the power of being really old… I maybe aged out of that competition”, says Hamm, who appears in the new film ''The Town''.
That’s not to say Hamm wouldn’t be interested in the movie, noting that he’d like Warner Bros to run the idea by him anyway.
It sounds like he just doesn't think they would want him for the role (due to age issues). Personally, I think they need an older Superman, but I agree that it might be difficult to convince Hollywood executives to avoid casting some guy in his mid-twenties.