Gray will probably be the top starter on the market if he hits free agency next year, there's little to no chance he takes a 1 year deal when a 3-4 year deal will be sitting there for him. Has any pitcher of his quality not gotten signed because of a comp pick attached? Losing a late 2nd round pick for a contender is a no brainer.
What's the point of trading one of the better young relief pitchers in the game who has 5 years of control left for more prospects? You hope of the prospects turn into a guy like Duran, trading him no makes absolutely no sense.