If the Rangers do, in fact, pull the trigger on a big trade for a mid-level starter, or even an ace, which player that we have to give up would you not want to trade away? Which player would hurt the most to get rid of (see John Danks and Adrian Gonzalez), either in the upcoming season or in future years?

Chris Davis?
Derek Holland?
Tanner Scheppers?
Martin Pérez?
Jurikson Profar?
Julio Borbon?
someone else?

Which player would hurt the most to get rid of, either in the upcoming season or in future years?

Answer, In this order:

Holland
Scheppers
Profar
Perez
Borbon
Davis

Nigh-Untouchable: Perez and Profar
Trade if you must, but only for the absolute right deal: Ogando, Holland, Scheppers. I'd also hate to see Beltre go now that he's starting to break out, but I think it's possible his value is as high right now as it will ever be.
Usable piece I wouldn't hate to see moved, but would continue rooting for him after he left the Rangers: Mitch Moreland
Get what you can: Davis and Borbon

Chris Davis is someone I want to trade so he's definitely at the bottom of that list.

Players I would most hate to lose, in order:

Perez
Moreland
Feliz
Alfaro
Holland
Scheppers
Robbie Ross (his GB/FB rate makes me think he's worth more than his current trade value)

Players I would trade for right package:

Profar
Sardinas
Erlin
Skole
Olt
Engel Beltre

Players who should be moved now, whi,e their value is at their peak:

Hunter
Davis
Strop

Trade Josh Hamilton: will never get a better price but who will have the bargaining chips - it is like making a trade for Pujols - SO IF a team makes such a trade they strip away their future. D0 NOT trade Davis or Holland- both still have HUGE upside with little value at the moment. If done do not be surprised when they become an A GON or Danks.