Its possible that Mebane gets cut but its highly doubtful that he will.
Right now the top three cut possibilities are:
1. Max Unger: Patrick Lewis is starting to look like he has a future, and the Seahawks can bring back Jeanpierre and Schilling on the cheap to compete as well as draft a body or two.
2. Zach Miller: Seahawks have Willson and Helfet (I believe) under contract, they could re-sign Moeaki on the cheap, as well as use a draft pick or two to the competition.
I think for these two players, its telling that the Seahawks were able to continue to win games without them.
3. Russell Okung: its hard to determine because the Seahawks don't have the OL depth you would like but at the same time Alvin Bailey has played solid both at LT and LG. If you move him up to starter status you are losing considerable depth on the left side. And while the Seahawks can save the most money by cutting Okung, his cap hit is pretty low for an LT these days. But he's also prone to injury and penalties that make his game inconsistent at times.
Mebane is a possibility. But after 2015 he's really your only true NT on the roster. Seahawks likely won't resign a 35 year old Kevin Williams.
And that means you're leaving the DT depth Tony McDaniel on the last year of his deal and Jordan Hill, who seems to injury proned at this point to be a full-time starter.
NTs like Brandon Mebane are hard to come by. And McDaniel is probably too tall to be the stout bowling ball they like. So it will be Jordan Hill at NT. Then its probably an undersized Cassius Marsh trying to take over for Hill's nickel DT role or someone else.
So I just don't see the logic of getting rid of Mebane... before he was I.R.'d, he was having a very dominant year, possibly his best year yet since becoming a NT.
You just don't cut guys who out-perform their contract on a consistent basis that are reasonably dependable.