DeBoer was moving Marleau to the 3rd line during the Finals run. I don't think the concern that DeBoer will play him above his capabilities is warranted. It just depends on what else we have up front. It seems to me, we will have Kane, Hertl, Couture, Meier, Labanc, Sorensen, Goodrow, Radil, and probably Karlsson, Thornton, and Marleau. Then maybe Gambrell and one other spot whether that's internal or a signing like Pavelski or Nyquist or Donskoi.
I can see this team trying to move Labanc into the top six next year which I think he will fail at and using Gambrell to replace him on the 3rd line with Marleau and Thornton. If Labanc is failing, putting him back with Thornton and having Marleau with Couture and Meier wouldn't be the worst utilization of talents.