Aaron Rodgers isn’t starting for the Pittsburgh Steelers today, but he will be suited up with at least a small chance of entering the game. According to Gerry Dulac, he will serve as the Steelers’ emergency third quarterback.
In order to enter the game, both Mason Rudolph and Will Howard would have to get injured or be disqualified by the officiating crew. Here is the official rule from the NFL website.
“An Emergency Third Quarterback is permitted to enter a game only if the club’s two active quarterbacks are unable to play either by disqualification or injury, including for example, if QB1 is unable to play and QB2 is being evaluated for an injury.