After Brock Purdy tore his UCL and Josh Johnson sustained a concussion in the NFC Championship game against the Philadelphia Eagles, the 49ers lost.
The Eagles just attacked the 49ers' run game after Purdy was pushed back into the game without the ability to throw. They cruised to the Super Bowl while San Francisco had little chance.
If that happens on game day, the NFL will help clubs this season. Multiple sources say a team can use a "emergency" quarterback on game days after a bylaw was enacted on Monday.
If two quarterbacks are injured or disqualified, the third can play. Each club may also designate one emergency third quarterback from its 53-play Active/Inactive List (elevated players are not eligible)
who will be eligible to be activated during the game if the club's first two quarterbacks on its game day Active List are injured or disqualified (activation cannot be a result of a head coach's in-game decision to remove a player from the game due to performance or condition).
In February, Dallas Cowboys owner Jerry Jones discussed such a restriction with Yahoo Sports.
"And boy, we don’t want teams without quarterbacks in these games where 50 million people are watching."