The X, Y, Z designations are needlessly confusing unless the terms are defined each time they are used.
Traditionally, the X was your split end on the weak side lined up on the line of scrimage to satisfy the requirement that there be 7 guys on the line. The Y is the in-line TE. The Z is the flanker on the strong side who may line up off the line of scrimage. If you run it that way, the split end can't motion but the flanker can. Theoretically, the split end is mano a mono with a corner whereas the flanker may run a combination route with the TE. Note there is no slot receiver designation; this the old school two-back set. Think McGee-Ron Kramer-Dowler. Of course we still see this from time to time, but these are almost always run plays with a lead blocker with the occasional short timing pass.
With the growing and now universal use of the slot receiver, some folks call the slot the Y receiver and the in-line TE simply the TE. Others still call the in-line TE the Y receiver the slot receiver simply the slot.
To avoid all the confusion, I find it easist to call the X and Z simply wideouts and with the 3 and 4 wide variations looking for matchups you'd prefer them to be interchangeable. The TE can be either in-line, slot, wideout or the H-back if he's in the backfield. Some refer to a TE that splits out to slot or wideout a "joker".
Now, I don't see Adams as an especially threatening deep ball receiver. He doesn't track and adjust to the deep ball all that well and he doesn't have the long speed that Nelson had and then lost. The 40 time notwithstanding, Nelson had a long strider's 5th. gear whereby he could separate downfield and he never got caught from behind. Adams doesn't have that; he makes his money chielfly on the quickness of his breaks and double moves.
It would seem a bonafide speed threat on the perimeter is in order even if you don't throw it to him all that much, which is probably going to be the case regardless with a rookie given Rodgers exacting standards.
