Here are the options:
1) Extend JD for max $$ for 7-8 yrs (you know he will accept nothing less)
2) Let him walk as a FA
3) Trade him for controllable assets
There are so many considerations here. Budget - tying down the budget to a limited # of players (Martin, Tulo, JD, EE?) leaving insufficient $$ to field a team without significant holes. Risk that Tulo range will decline and he needs to be moved to 3B? Vlad's prospect grade (A prospect? - anticipated elite, AS level)?
Shatkins is going to consider all this and other things we don't know about (JD medical reports), and yes, potential JD replacements including from the farm when making a decision. They wouldnt be doing their job if they didnt.