While looking for something else, I came across this post from 5 years ago.
The Espinosa deal was a bad idea at the time. Pomeranz was having a career year and getting lots of luck out of his new cutter. Using the highly ranked Espinosa to obtain him was an overpay. Pomeranz fell back to earth but was serviceable. In hindsight, Espinoza had major injury issues and only appeared in MLB recently in a bullpen role. His ceiling now isn't what we once thought. HOWEVER, it was a bad trade, but not as bad as we thought at the time. They should have used the highly ranked Espinoza on a better pitcher IMO.