It wasn't a big sample size, but Mullens filled in admirably, passing for 2,277 yards with 13 touchdowns and 10 interceptions through those eight games before returning to his backup role the next season—following a training-camp competition with Beathard.
Analytics site Pro Football Focus recently ranked the backup quarterback situations in the NFL, and San Francisco came in at No. 9, mostly due to Mullens.
"Beathard's performance in (head coach) Kyle Shanahan's QB-friendly scheme was much worse than Mullens," wrote Ian Hartitz. "At this point, Beathard's claim to fame is helping feed Carlos Hyde an egregious 88 targets during the 2017 season."
Ouch.
Hartitz notes that Mullens, on the other hand, had a less-than-ideal turnover and sack total but averaged 8.3 yards per attempt while throwing for 284.6 yards per game.
Mullens could be a good quarterback. For now, he is a good enough backup to fill in for Garoppolo, if needed. An undrafted-free-agent signing in 2017, he is entering his fourth season with Shanahan.
"There's a real chance that he's a #good QB," wrote Hartitz. "The only rookie-signal callers (minimum eight starts) to average more adjusted yards per attempt than Mullens since the 1970 AFL-NFL merger: Dak Prescott, Robert Griffin, Ben Roethlisberger, Russell Wilson, and Dan Marino."
Michael Lombardi of The Athletic reported that the 49ers like Mullens so much that they passed on trade offers for the backup quarterback.
"They were asking about him, and they turned down every trade offer for Nick Mullens," Lombardi said before the draft. "They wouldn't trade him."
For now, San Francisco can be assured that they have a solid backup plan heading into the 2020 season.
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