Allen became a 49er on May 8, 2023, signing as a free agent. The 49ers, who up to that point seldom kept a third quarterback on the 53-man roster, kept Allen as a No. 3 all season behind Purdy and Sam Darnold after the previous year’s injuries to Trey Lance, Jimmy Garoppolo, and finally Purdy in the NFC Championship Game. Allen did not take a snap.

The Green Bay Packers defense won't have to face quarterback Brock Purdy when the injury-depleted San Francisco 49ers come to Lambeau Field for the Week 12 showdown Sunday. Purdy suffered a shoulder injury in the 49ers' game last week and is among multiple players on the team's injury report.

Brandon Allen will start in place of an injured Brock Purdy when the 49ers (5-5) also have to play without Nick Bosa on Sunday at Green Bay (7-3).