On Friday, 49ers coach Kyle Shanahan informed him that he also had won the job over C.J. Beathard to open the season as the team's backup quarterback behind starter Jimmy Garoppolo. The 49ers kept the news quiet until Monday, when Mullens told the media he won the backup job.
The 49ers open the regular season Sunday at the Tampa Bay Buccaneers.
Mullens began the past two years on the practice squad, but he quickly rose to prominence last season after replacing Beathard in the starting lineup for the team's Week 9 game against the Raiders.
Mullens, who signed with the 49ers in 2017 as an undrafted rookie from Southern Mississippi, compiled a respectable 90.9 passer rating. He averaged 285 passing yards per game, ranking him fourth all time through eight games behind Patrick Mahomes, Andrew Luck and Cam Newton.
Beathard was a third-round draft pick in 2017. In 10 starts over his first two seasons, Beathard threw 13 interceptions with 12 TD passes. He also was sacked 37 times.
Beathard and Mullens had similar statistics during the preseason this summer while both were in competition for the backup job.
[RELATED: Bosa, Verrett return to 49ers practice]
Beathard completed 64.9 percent of his attempts for 280 yards with two touchdowns, one interception and a 94.4 passer rating.
Mullens completed 64.7 percent of his attempts for 229 yards with two TDs, one interception and a 91.4 rating.
Nick Mullens wins 49ers' backup quarterback job over C.J. Beathard originally appeared on NBC Sports Bay Area