I love speculative shit like this. Detective work time.
My guesses, in order of likelihood:
Bryant:
Before I even read the tweet saying it was a defensive lineman, I thought of Bryant who is likely a goner after this season anyway (roster bonus) and who hasn't lived up to his second contract. Also, there is a LOT of competition for Bryant's job right now: Bennett, Howard, probably Jesse Williams too (if not now then in the future). Seattle likes to have a replacement on hand before they release paid veterans, and they made several moves to replace Bryant his offseason.
If I was Bryant, I'd be nervous. I don't really care about the camp reports, Bryant has 3 seasons at the 5-tech now and has not performed up to his current pay level. The reason he's still here is because he's a physically rare profile and a good leader, but it looks like Seattle has found more guys with that rare profile (Jesse Williams, etc) and last season showed that they had plenty of leadership on defense already.
The only reason I don't think it's Bryant is because most of his 2013 salary is guaranteed, so releasing him right now offers almost no cap relief. 2014 is a very different story, though.
Clemons:
Clemons is also being paid a lot and has seen the team make several new additions to compete. Perhaps more alarmingly, there are major changes underway to the LEO position itself which makes the position less strict to find talent for. Seattle is already building their post-Clemons defense, so his being nervous makes a lot of sense. If immediate contract fears are the motivating factor, then Clemons would make the most sense.
McDaniel:
He's on a vet minimum contract ($890k), and was basically signed to replace a starter from last season. His resume is somewhat underwhelming though, and he does classify as a veteran. He may not be paid highly, but you'd assume that he signed here at least feeling like a roster spot was in the bag, which right now looks far less certain. The Seahawks have a lot of bodies at the 3-tech right now. I could see it being McDaniel.
McDonald:
He's making the minimum RFA tender. He shouldn't be anymore worried about keeping his job than he's ever been.
Mebane:
I think Seattle would be crazy to release Mebane, especially since his $5 million average salary is a bargain. If they did release him, he'd be replaced by Williams or Hill, both rookies. Hill is NOT an NFL caliber 1-tech, even by 3-tech standards his run defense is on the low side of mediocre. Williams could do the job, but Seattle's pass rush would suffer, and Williams knees are no sure thing, and we'd have no real depth behind Williams. That plus, the team seems to like Williams for the 3-tech in 2013. Again, releasing Mebane would be crazy, and I see no reason for him to be nervous. But who knows, I didn't see the Housh release coming either.
Players I'd rule out:
Avril:
We need him in the first four weeks pretty badly.
Bennett:
He's a huge part of our new defense, plus he's versatile, and his contract is only a modest burden, with nothing owed after this season. He's also playing very well, per reports, and is coming off a breakout season.
