the tigers did not have to trade verlander or martinez. verlander was under contract for two more years.
the real criticism i have is not that they traded them, but the very poor return they got, especially for martinez. one can argue that the verlander return was decent on paper, but the martinez trade was abysmal and universally panned at the time. you dont have to trade him just to trade him. they chose to take that return because avila considered it a good return.
the cubs just chose to let wilson contreras walk foe a draft pick rather than take what was offered. is that better than dealing martinez for junk rather than keeping him? dunno.