NFL backup quarterback rankings: Tiering the best, worst and untested No. 2 signal-callers

At one point during the NFL's late Sunday window this past weekend, four of the eight teams on the field were using their backup quarterbacks. That's not supposed to happen in the NFL, which has embedded deep injury protections for quarterbacks into its rule book to prevent, say, Nathan Peterman from ever taking a snap for the Las Vegas Raiders.

But there was Peterman on Sunday, filling in briefly while starter Derek Carr was examined for a possible injury. Mike Glennon, meanwhile, stepped in for injured New York Giants starter Daniel Jones. Andy Dalton took some snaps while Chicago Bears rookie Justin Fields was examined. And rookie Trey Lance started for the San Francisco 49ers while Jimmy Garoppolo nursed a calf injury.

In most cases, backup quarterbacks are triage in a crisis. The Bears were the only team of the four to win in Week 5, and overall this season, backups -- defined here as someone other than a Week 1 starter -- have lost 10 of the 14 games they've started.

Fortunately for the NFL, they haven't been needed much in 2021. The 37 starts by backup quarterbacks through five weeks is the fewest since 2012 and the third-lowest total since the NFL expanded to 32 teams in 2002, according to ESPN Stats & Information. But five are expected to start in Week 6, and now is a good time to take stock of the quality of reserves around the league. What follows is a cross-section assessment of the best, the worst and a few in between.