You know me: no player is untouchable.
Of course, I have players I'd much prefer to keep, and I tend to value years of control and upside potential more than some, but I'll trade anyone for a better return. I'll trade anyone for an equal return, if the return is in an area of greater need, and the step up in that area looks to be greater than the step down from the area we traded away.
I prime example would be trading Duran for a 1 slot SP'er. How big is the step down to Anthony or more time from Abreu, Ref and rafaela in the OF? Weigh that step down vs the step up from a top SP'er vs Fitts or Crawford in the rotation. Also, moving Fitts or Crawford to the pen or rotation depth would improve that roster slot as well. Alternately, we could trade Anthony and keep an already excellent OF intact.
If I had to list our who I'd prefer to keep, it would be like this:
1. Houck. 2. Anthony, T3. Campbell & Duran, 5. Teel, 6. Mayer, T7 Casas and Bello, 9. Slaten, 10. Arias