The more I think about it I wonder how Morse fits what Tampa needs? They don't want expensive contracts. Morse has one year left on his deal and if he has a big year will get a significant raise. With their budget, Tampa probably wouldn't sign Morse long term so they would be left with Morse for one year and Espinosa.
I just don't see them trading Shields for that return. If Morse were signed to a reasonable contract then I could see it. Maybe Espi, Moore & something else?
Morse fits a need for a productive bat to play DH or 1st. For the past few contending years, they have filled in those positions on a year to year basis (2011, 2102). He'll be making less than they were paying Pena last year. They had $12MM+ in Scott and Pena last year, so Loney and Morse saves money. They have an abundance of cheap young starters (Price, Hellickson, Moore, Niemann, Davis, Cobb, Archer, Torres), which is why most writers looking at that roster figure that Shields (or possibly Price) is available. Doesn't mean they have to do the deal, but if they do want to move Archer or Cobb to the rotation, they likely can do the deal, save salary, and get a production out of it.
It's likely not happening, but Espinosa would be superior to most prospects they could receive. They may prefer multiple prospects and roster help for any deal for Shields, but that is more of an issue than them not wanting a longer term MI and a short term cheap plug in for 1st / DH.