To add onto your question, I think it must be a player at #56 that should be projected to contribute in a major role say at least 40% of the snaps should be a realistic option.
On offense pick #56 won't beat out QB, RB, LT, RT, C, #1 TE, #1 WR, Slot WR, FB
That leaves RG, LG, #2 WR, and #2 TE as positions where the most playing time is up for grabs
On Defense pick #56 won't beat out FS, SS, #1 CB, #2 CB, SLB, MLB, RDE, LDE, #1DT (Mebane), #2 DT (Bennett)
That leaves #3 DT, WLB, Nickle CB as the positions where the most playing time is up for grabs
So heres my order by priority of the positions where I think playing time is actually up for grabs
WLB, #3 DT, Nickle CB, #2 TE, #2 WR, RG, and LG.
So a big surprise that mabye makes the most sense but that would throw people off would be a WR at #56, With the aqusition of Harvin most wouldn't expect us to add another WR so early. I can see the logic becase Tate is a FA next year and PC like big WR's. This would be almost be like a redshirt year while the big WR would fight Tate for the #2 and likely get most time in the redzone or backing up Rice. If Rice goes down we will sorley lack a large WR target so some insurance would be nice, plus as expectations for that WR would be low. That's a plus because it seems to take most WR's time to develope.
Thoughts?