I’d think trading him in-season this year would be more likely to yield a scenario where the Braves don’t have to eat money and/or receive at least a middling return—though I do wonder how his market might be improved if the Braves offered to cover his 2018 salary (already budgeted) but not his 2019 dough.
This all might be academic if he can’t pitch healthily and solidly over the next two months.