The Seahawks won't know their backup situation until they settle on a starter.
Flynn passed for 731 yards with nine touchdowns and two interceptions in his two career starts, both with Green Bay. He's the projected favorite to start for the Seahawks. It's likely a bad thing in the big picture if Flynn fails to win the starting job this season, but the backup quarterback situation would improve under such a scenario.
Jackson was 7-7 as the Seahawks' starter last season despite playing through a torn pectoral muscle. He has a 17-17 career record as a starter. Those numbers should be comforting if Jackson is the backup.
Wilson has a strong arm, has shown instant command of the offense and possesses ample intangibles. He has never played in even an NFL exhibition setting, however, so it's premature to say he's ready for the backup role.
Like the Cardinals, the Seahawks will take a potential starter into the regular season as a backup. They could do worse and did last season.
Confidence rating (out of 100) if the starter is out for an extended period: 60.