Let's face it, Moss coming back is a long shot. But at some sort of minimum salary, I don't see how the Pats pass that up. While they've won with him, their offense (particularly Welker) is clearly not what it was without him. Even if Moss isn't what he was two years ago, he draws double teams. And if teams stop doing that, he's still good enough to destroy people.
And at the minimum, they could always cut him.