11. Nick Mullens (2018 to 2020)
Nick Mullens ends up lower on this list than Blaine Gabbert because he had a much more talented team around him and did less.
Mullens signed with the 49ers as an undrafted free agent in 2018. He had an amazing first game against the (then) Oakland Raiders, throwing for 262 yards, three touchdowns and no interceptions. He would win his first start 34-3.
He would, however, prove to not be starting QB material for the team and would be something of a serviceable backup instead.
Mullens ended his tenure with the team posting a 5-11 record as a starter.