Rodgers suffered his second concussion of the season Sunday in the Packers' 7-3 loss to Detroit, missing the entire second half as Flynn struggled to provide an offensive punch for the Packers.
Rodgers also sustained a concussion in the season's fifth week against Washington but it wasn't serious enough to make him miss a start. He will now miss Monday night's game against New England -- his first absence since taking over as Brett Favre's replacement in 2008.
Flynn was limited to just 177 yards and was intercepted once on 15-of-26 passing last week. In his 27-game career as a backup, he has thrown 46 passes.
Rodgers, meanwhile, is the NFL's fourth-ranked passer with a 98.5 rating, tossing for 3,289 yards with 23 touchdowns and 10 interceptions.