From the Preds side, I would give Stamkos and his whole contract away for free, but I wouldn't pay somebody to take him nor would I take equivalent-term negative value player assets back for him.
Maybe at most I'd retain $2M and say you could have Stammer at $6M for free? If I thought I had a good line on useful ways to spend that $6M saved on July 1st. But still no draft picks attached, no salary dumps coming back to the Preds. Otherwise, he's still an ok player, he'll get 25 goals, second-best on our team, and it's not like we have anybody else pushing for his job atm, nor do we have any likelihood of attracting any better UFAs who we'd need the Cap space for.