You guys may be looking at this wrong. The Sox didn't just let Papelbon go. They were so financially strapped with the Crawford, Agon, Beckett and Lackey deals they were not able to match or even overpay to keep Papelbon in town. I mean really, they had to trade Scutaro to be able to sign Ross. Where was the extra 15M per year coming from to match Phillies offer?
Now if the team had the financial flexibility it has now, I think they had a better chance of matching or even overpaying a bit to bring him back.