Back-up quarterbacks in the NFL have different roles depending what team they are. Sometimes they are simply an emergency option if a superstar quarterback gets hurt. Other times they can be mentors to a young quarterback or can even provide competition to quarterbacks who have not earned their job long term yet.5 Best back up quarterbacks in the NFL#5 - Drew Lock, Denver BroncosDenver Broncos Quarterback Drew LockDrew Lock was decent in just one season as a starter for the Denver Broncos. He started 13 games, throwing for nearly 3000 yards and 16 touchdowns. The issue was 15 interceptions, but that's not uncommon for a young quarterback. Despite a respectable first season, he lost the the starting quarterback job to newly signed journeyman Teddy Bridgewater.James Merilatt@jamesmerilattVic Fangio's record...With Drew Lock = 8-10With other QBs = 9-15So who's the problem again? #Broncos9:25 AM · Nov 15, 202174387Vic Fangio's record...With Drew Lock = 8-10With other QBs = 9-15So who's the problem again? #Broncos#4 - Jacoby Brissett, Miami DolphinsMiami Dolphins QB Jacoby BrissettDaniel Oyefusi@DanielOyefusiFlores says he expects Jacoby Brissett, who injured his knee against the Ravens, to be active for the Jets game and back up Tua.10:52 AM · Nov 17, 2021161Flores says he expects Jacoby Brissett, who injured his knee against the Ravens, to be active for the Jets game and back up Tua.Jacoby Brissett registered over 6000 yards with 31 touchdowns and 13 interceptions in two years as a starter for the Indianapolis Colts. He was replaced twice, by Philip Rivers and Carson Wentz. He now serves as a back-up to Tua Tagovailoa for the Miami Dolphins. Filling in for six starts, he threw for five touchdowns and four interceptions.Also Read: Who is Philip Rivers' wife, Tiffany Rivers?