Interesting choices. I see the summary of the contenders as:
Solder + Seabass is worse than last years tackles, but not a big drop (pray no injuries to these two guys, no one wants to see Cannon on the field after this pre-season)
Wendell is much worse than Waters (or you could say Wendell (C)+Connolly(G) is much worse than Connolly(C)+Waters(G)). But few people consider the interior of the offensive line to be a critical spot on the team.
TBD if Chandler Jones is a drop from Carter, probably is worse this year but CJ should have his moments
Which leaves BJGE. As far as I am concerned, he is replaced on the roster by Bolden. How can that be considered anything but an enormous drop? Vareen is already injured and Ridley still has questions about ball security, so it is not like we don't need another reliable 1st/2nd down option at RB.
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If everyone on the current 53 plays to their best (within reasonable expectations), Waters is the biggest loss.
If injuries hit the wrong players, Light will probably be the biggest loss.
If our young RBs play exactly like they did last year (and not at much higher level we are hoping/expecting), it will be BJGE.
So, I voted BJGE, since the domino effect of a rushing game that a defense doesn't respect, coupled with a shaky line, would mean that Brady would get hammered.