The whole concept of who is a starter and who isn't is kind of dead, anyway. I've seen numerous times where a 'starting lineup' is announced, but the guys that actually take the field for the first series are quite a bit different. This especially applies to positions on the periphery like WRs and DBs. They announce 2, but often start the game with either 1 or 3. They announce 2 CBs, but start off in nickel coverage. Hey it wouldn't surprise me if they start the D off with a Bandit package out there, in a 4-2-5 or something.
Exactly. The "starting lineup" should just be the 11 players who play in the positions that would make the "All-Pro team", ie.
QB, RB, FB, 2*WR, TE, LT/RT, C, LG/RG
front 7, 2 corners, 2 safeties
I say front 7 because teams so obviously have either a base 4-3 or base 3-4, so some flexibility there. It doesn't matter if the FB doesn't play their first snap, or only plays 5 snaps all game, if he's the #1 FB on the depth chart, he's the starter.