Mac Jones was the 12th-most efficient quarterback in the NFL last season -- so why is he still a backup in San Francisco? And how does Tua Tagovailoa, a top-eight efficiency quarterback three years running, end up as the No. 2 name on a list of backups? These are the five quarterbacks who decide whether a lost month in October becomes a lost season, and the ranking says the 49ers are sitting on the most valuable insurance policy in football. Jacob makes the case that Jones has already played his way into another starting conversation. We cover all this, plus Fernando Mendoza and the rest of the top five backup quarterbacks in the NFL going into 2026, in a rapid-fire ranked rundown hosted by PFN's Jacob Infante. Every name here comes with a real argument attached -- efficiency numbers, depth chart reality, and where each quarterback goes next. Twelve teams will need their second quarterback before Thanksgiving. The ones holding a name off this list are the ones still playing in January...