If Seattle retains six wide receivers, four running backs and four tight ends, sacrifices will be made elsewhere. But where? I will see if I can figure that out.
Left Tackle
Starter: Russell Okung
Backup: Ray Willis
In the mix: Mansfield Wrotto
Wrotto is in the mix but not because of tenure, but because of versatility. His ability to play guard, tackle or even center in a pinch gives him an edge over comparable linemen.
Left Guard
Starter: Ben Hamilton
Backup: N/A
In the mix: Mitch Erickson, Mike Gibson
Center
Starter: Chris Spencer
Alternate: Max Unger
Backup: Steve Vallos
In the mix: Jeff Byers
Unger is listed as OC/G on the Seahawks roster. That keeps the controversy alive, but Seattle does not have much depth at guard. If it moved Unger to center, it might have to move Spencer to guard. Vallos is in the mix because he has some regular season experience and some of the abilities Gibbs wants in a center: squat, quick, smart. I think Byers is practice squad bound, if he makes it that far.
Right Guard
Starter: Max Unger
In the mix: Mitch Erickson, Mike Gibson
Right Tackle
Starter: Sean Locklear
Backup: Ray Willis
In the mix: Mansfield Wrotto, Jacob Phillips
And so, with that, we see that this is a pretty thin unit. It's an interesting setup. Okung, Hamilton and Unger have enjoyed good health. Spencer and Locklear have not. Gibbs emphasizes continuity and in this case that might mean something. Gibbs might sacrifice talent to ensure continuity. I don't know that Seattle has that luxury just yet, but if Spencer and Locklear struggle with injuries, I could see them shortlisted for replacement.
I project Seattle to start the season with Okung, Hamilton, Spencer, Unger, Locklear, Willis, Vallos and Wrotto on the roster. Chester Pitts will remain on the physically unable to perform list, and Byers and Phillips could land on the practice squad. Vallos could be replaced by one of Erickson or Gibson, as could Wrotto. Wrotto might have the edge because he can play guard or tackle. Willis can play guard or tackle and could back up both left tackle and right tackle.
That seems thin, maybe even unrealistically thin, and it is thin, and it might become thinner still. Vallos might not be retained. Wrotto might not be retained. Injuries may fell roster bound players. Starters will have to stay healthy. Depth is essential, but not needing it is even better.