Papelbon has a good year (2008 repeated), and the Sox decide they feel comfortable keeping him, Bard and Jenks together as a three-headed monster at the back of the pen, so they decide to set a limit on him at 3/36 and put that offer on the table, Papelbon tests the open market, doesn't receive an offer that matches the 3/36 offered by the Sox and decides to return.
You don't know the value the Sox have currently set for Papelbon or the value they will set for him after the year. None of us do, and discarding the scenario because you think you know the FO's plan is an exercise in futility. He may be back, he probably won't, but you don't know that, and neither do the rest of us.
However, the possibility exists (no matter how much you stomp your feet and scream otherwise) that circumstances may have him returning for the Sox after '11. Spare me the "opinion" part of the argument and focus on the objective viewpoint of the issue, which is:
He likely won't be back, but there's a chance he could be, and neither i, nor anyone here, can discount either possibility, because we don't know the FO's actual line of thinking. All we have are speculation and press clippings.