I think if a trade for Price was structured that way it would be more acceptable. Medlen has only two years of contractual control, so not so much surplus value as Wood.
My grand plan would be this. Sign McCann. Offer Medlen and Gattis for Price. I think that's a bit of an overpay, but it would give us a shot to get Price. If not we can live without Price. If we get Price, his salary is partially paid for by not signing Hudson and giving up Medlen, who between them would make about $10 mil.
Valuing Gattis is tricky. I think his future development is more uncertain than other players his age. Risks in both direction. Also his value is higher for an American League team. The question is how many American League teams would really want him. There might be one or two who see great value in a player like him. If the Rays are one of those teams, Medlen plus Gattis for Price could well fly.