Make them throw in a prospect say...a Scott Sizemore, or a Matt Joyce, then I would. But trading a young, cheap valueable arm for a free agent to be EXPENSIVE SS is NOT an ideal trade, IMO. So again, if Detroit is willing to throw in a solid prospect with Renteria, then yeah I would Marmol for Renteria/prospect. But the first goal, should be to trade Dempster before considering moving Marmol. Let's shoot for the moon and demand Rick Porcello! In all seriousness, it depends one whether you think Marmol has the potential to be a starter in the future. If he will be a reliever his whole career due to mechanics-related concerns, then Renteria for him straight-up would be robbery. It probably is, anyway, because regardless of his potential, Marmol will probably never get a chance to start for us anyway (and Detroit is exactly the type of team/front office that would give him a shot at it).