IMO young controlled arms who belong to contender teams like Carrasco are pipe dreams. On the other hand, if you want a guy like Teheran, Gray, etc. you will likely have to give up a big haul of prospects. Also, aces like Sale are franchise players. They are untouchables. The WS will lock out this guy -- They won't s*** the bed as we did with Lester.
IMO 2nd-tier arms who can pitch at times like No. 1s and have large contracts or will become FA soon could be more realistic options coming from L-teams.