Seattle's offensive line regressed even with Charles Cross back
To be sure, for most of the season the Seahawks have had to deal with backups playing most spots along the offensive line and that has somewhat limited what the offense was trying to do. For instance, a team doesn't throw deep all that much if they aren't sure how well their blocking will hold up in front of the quarterback as the longer play is developing in front of them. But against Cincinnati, even with starting left tackle Charles Cross back, the offensive line wasn't as good as in recent weeks even though Seattle's offensive scheme didn't change all that much.
Maybe part of the issue was that starting left guard Damien Lewis was missing. Over the last couple of years, Lewis has been the Seahawks' best and most consistently good offensive lineman. Seattle also doesn't have a natural replacement for him. Phil Haynes played in place of Lewis in Week 6 and Haynes was bad.
Haynes allowed 4 quarterback pressures, 2 sacks, plus a quarterback hit, and a hurry. He also picked up a penalty. If Lewis can't go again in Week 7 due to his ankle injury, maybe Seattle could have Jason Peters step in. Peters was signed earlier this year and is a future Hall of Famer who simply happens to be old for an NFL player.
Jake Curhan has been solid at right tackle while presumed starter Abraham Lucas is out with a knee injury. But he was atrocious against the Bengals and allowed 7 pressures, a sack, and 5 quarterback hits. Even Cross wasn't that great as he allowed 4 pressures and 4 hurries.