It has been discussed a lot elsewhere---Terry is, as usual, pretty smart on this, and we have some other guys who have done some good "counting" of how many retentions needed for opening up new recruiting possibilities.
The key people to me have been the several guys who are on the two deep. Harrison Smith and Gary Gray are "musts" in my mind. My memory is saying that Dever is in this class too, and, if so, you'd hardly let your starting right tackle go. The debate would be in the second teamers like Nuss, Romine, Ragone, Nkwanko. Functional O-linemen are hard to part with, but with the emergence of Watt, the potential of Lombard and Nichols, and the big-time qualities of Hegarty, who knows what the staff will do about Nuss and Romine?? If Rudolph returns, I'll bet that Ragone goes. Eifert, Welch, and Koyack are all there and raring for action. Even if Rudolph leaves, I'd not be surprised to see Ragone let go anyway.
With the emergence of Schwenke, the flexibility of Hafis Williams to play DE [as Nix moves in to assist Cwynar], and the hoped for coming of Tuitt and Springman, I would be very surprised to see Nkwanko be offered a fifth---but I'm not in the war room so this is worth about a wooden nickel.
Forgot about Brian Smith's situation. Up until last two games replacing Carlo, I'd have said no way to a fifth year, but if Kelly/Diaco want to try him in the middle rather than outside, then I'm changing my mind. Even then, though, this motherload of potentially great linebackers we have in stable and verballed makes me wonder if it makes good sense. I absolutely want to see NO strategy that lessens Shembo's presence on the field, and wouldn't mind seeing a glimpse of Spond and Moore next year either [not even mentioning Rabasa, Councell, Grace, [knock,knock] Ishaq Williams...etc].