MORE: Super Bowl 54 predictions from SN’s expertsWho is the Chiefs’ backup quarterback?Patrick Mahomes is backed up by 11-year NFL veteran Matt Moore. The 35-year-old signal-caller has started 32 games in his NFL career, including two this season when Mahomes was out with a dislocated right kneecap. Moore went 1-1 in those starts, defeating the Vikings and losing to the Packers. For his career, he’s 16-16 as a starter, going 7-6 with the Panthers, who originally signed him as a free agent out of Oregon State, and 8-9 with the Dolphins, where he spent seven seasons. His best season came with Miami in 2011 when he started 12 games, threw for 2,497 yards, and posted 16 TDs (all career highs). For his career, he’s completed 60.1 percent of his passes and has a 49:36 TD-to-INT ratio. Considering Moore was out of football in 2018, he performed well in his stint as the Chiefs’ primary QB this year. Counting the game in which Mahomes got hurt, Moore was 59-of-90 (65.6 percent) for 659 yards, four TDs and no turnovers. The Chiefs scored 67 points in just over 10 quarters with Moore under center. Obviously, Moore doesn’t have the arm strength or the overall talent of Mahomes, but the Chiefs didn’t change their offense much with him at quarterback. They took fewer shots deep downfield, but the overall run-pass ratio was about the same. Clearly, coach Andy Reid trusts Moore to run the offense, and with the receiving weapons around him, he was able to adequately get the job done earlier this year. There’s an old saying in NFL circles that the backup quarterback is the most popular guy in town, but if a second-string QB is forced into action in the Super Bowl, there’s no grace period — he must produce. As the Chiefs and 49ers get set for Super Bowl 54, neither of their fanbases wants to think about the possibility of Patrick Mahomes or Jimmy Garoppolo getting hurt, but considering both have suffered serious knee injuries in the past two years, it’s worth knowing who their respective backups are. Both the Chiefs and 49ers’ backup QBs have started for their teams in the past two seasons, and both performed admirably when called upon. While neither possesses the talent of Mahomes or Garoppolo, both have proven themselves at the NFL level. Let’s take a closer look at the Super Bowl 54’s two most important backups. Who is the 49ers’ backup quarterback?Jimmy Garoppolo is backed up by 24-year-old Nick Mullens, who is in his third season in the NFL. The undrafted Southern Mississippi product started eight games for the 49ers in 2018, going 3-5. He impressed at times, totaling 2,277 yards while completing 64.2 percent of his passes and throwing 13 TDs. However, he also threw 10 INTs — at least one in all but two games. His two best performances came in his NFL debut, when he completed 16-of-22 passes for 262 yards, three TDs and no INTs in a 34-3 win over the Raiders, and in a Week 15 win over the Seahawks, when he completed 20-of-29 passes for 275 yards, one TD and no INTs. At just 6-1, 210 pounds, Mullens doesn’t have the ideal size to play QB in the NFL, but he makes up for that with a willingness to throw downfield, as shown by his 8.3 yards per attempt last year. He played in just one game this season but didn’t attempt a pass. He beat out former Iowa QB C.J. Beathard for the backup job in the preseason. Beathard started 10 games for San Francisco in 2017 and ’18, going 1-9 in those contests. Mullens has a chance to be the second former Southern Miss QB to win a Super Bowl, joining Brett Favre.