When you trying to move the unmovable, the difficultly comes in trying to make your offers more attractive to others than what they already have sitting in front of them.
When Atlanta traded Melvin Upton, Jr. to the Padres, the ‘carrot’ was clearly their chance to land Craig Kimbrel. Curiously enough, Upton has been a little bit better since then, Kimbrel perhaps a little worse.
When Chris Johnson was traded to the Indians, the Braves took back Michael Bourn and Nick Swisher.