The obvious counter-argument here: even when he has been healthy, he's looked like a fringe NHL Dman, on a team that not only needs defensive help, but has plenty of fringe NHL Dmen.
You'd be onto something if he looked like someone capable of stepping into the top 4, or even an established top 6 guy, but he just doesn't look like a guy that you should be banking on turning intos something significant.
He's given some major right handed Jake Gardiner vibes at times - I know he's young, and Dmen typically peak much later etc., but that would be the very reason why I would consider moving him this off-season; see if you can find a team that views him in those similar lines, and examine what that return would look like, even if he's in a package.