So keep them them for their prime and then LTIR them or trade them at 36?4 D past their prime... I plan on being a Leafs fan for longer than 4 years, so it'd be nice to have a GM that thinks past the current year.
D-men age a little better then forwards and can maintain form until 34-35 or beyond.
If things go well we're only looking at a year or so of declined play by the end of the deal, and they can be LTIR'd at that time anyways.