NFL teams start a combined 22 offensive and defensive players in any given week. Sure, that starting lineup is important, but those 22 are hardly the only ones who can play a pivotal role in deciding who wins and who loses on Sundays.
NFL defenses play two-thirds of their snaps (conservatively) with five defensive backs on the field; we call it "nickel." That extra defensive back? He may as well be a starter when factoring in overall impact and contributions. (Think about just how much slot corner Aaron Colvin meant to the Jaguars in 2017; enough that he earned a contract for $9 million a year this offseason from Houston.)
A backup quarterback might not play at all in a given year -- that's the best-case scenario for an NFL team -- but still has incredible value. (Nick Foles, anybody?) As Philly has shown, a capable fill-in quarterback is a pivotal ingredient for a championship-caliber team. And any roster, really.
With that in mind, let's run down the NFL's top 10 backup quarterbacks:
1. Nick Foles, Philadelphia Eagles
Experience: Eighth NFL season, Super Bowl LII MVP
Why he's here: We mentioned him already and few other backup quarterbacks have achieved what Foles accomplished last postseason. He has been up and down as a starter during his career, which is part of the reason why he bounced around as much as he has. But, with the stakes at their highest, he has shown he can be a guy who thrives within an offense. Philly has the right infrastructure in place to maximize him.
2. Teddy Bridgewater, New Orleans Saints
Experience: 28 career starts, 28 touchdowns, 22 interceptions
Why he's here: Some believed teams that were less than 100 percent certain about their starters might consider prying Bridgewater away from the Jets at the end of this preseason, but New Orleans did the deed to insulate its quarterback depth chart. A colossal knee injury cost Bridgewater all of 2016 and while he hasn't found a starting spot since, he's bound for one eventually, be it as the heir apparent to Drew Brees down the line or somewhere else.
3. Ryan Fitzpatrick, Tampa Bay Buccaneers
Experience: 14th season, has started for seven different NFL teams
Why he's here: Fitzpatrick is currently serving as the Buccaneers' starter and it sure seems possible that he won't concede the job upon Jameis Winston's return from a three-game suspension. Fitz has a shootout mentality (at times, costing him by way of interceptions) but he can push the ball down the field, as has been abundantly clear through two weeks of this season. He became the first player since 2014 to record back-to-back weeks of 400-plus passing yards and four-plus passing touchdowns. He's a beloved member of the Bucs' roster.
4. Baker Mayfield, Cleveland Browns
Experience: Rookie
Why he's here: The Browns have resisted starting Mayfield to this point, but it won't be long before he takes over as the centerpiece of this franchise. While he has yet to take an NFL regular-season snap, his college accuracy and small sample size of preseason play suggest his upside is immense. It has been forever since the Browns had a quarterback situation they felt really good about, but Mayfield has a chance to cure some woes.
5. Josh McCown, New York Jets
Experience: 16th season, 17,168 career passing yards
Why he's here: The Sam Darnold era began right away for the Jets and I'm not sure they could have a better mentor for him than McCown. He is immensely -- and I mean immensely -- respected around the league and, more importantly, within the Jets organization as a player who will serve in any role he is asked, which for now is as the tutor to Darnold. It's apparent just how much of a role he has already played in aiding Darnold. McCown also has the on-field aptitude to play sturdy football when thrust into action; we saw that in 2017 when he completed 67.3 percent of his passes with 18 touchdowns.
6. Jacoby Brissett, Indianapolis Colts
Experience: Third NFL season, has started 17 games
Why he's here: Brissett served as the Colts' starter for almost all of the 2017 season and considering the brief window he had to learn the offense (he was acquired eight days before the regular-season opener), he performed quite well. He has excellent football IQ and character, earning praise from teammates for his toughness. While not a high-upside player who may one day serve as a team's long-term starter, he's an excellent backup to Andrew Luck.
7. Colt McCoy, Washington Redskins
Experience: Ninth NFL season, 25 career starts, 26 touchdowns, 23 interceptions
Why he's here: McCoy hasn't attempted a regular-season pass since 2015, serving as the insurance policy to Kirk Cousins and now Alex Smith. But he has been well-regarded for his readiness and knowledge of the offensive system in Washington; the Redskins proactively signed him to a contract extension this offseason. He has good accuracy and functional mobility. He doesn't have a cannon arm, but he's a good fit for what Washington needs in its signal-caller.
8. Josh Rosen, Arizona Cardinals
Experience: Rookie
Why he's here: For now, Sam Bradford is the Cardinals' starter. For now. But Rosen, with his undeniable arm talent, stature and ability to stand tall in the pocket, will eventually take over this job and is the pivot point for this franchise. If he becomes the player that some forecast him to be -- and there were those in NFL circles who believe he has the highest ceiling of any rookie quarterback -- Arizona's outlook is secure for quite some time.
9. AJ McCarron, Oakland Raiders
Experience: Drafted in 2014, three career starts, 11 total appearances
Why he's here: Though the McCarron experiment in Buffalo flamed out before the season begun, he has landed in a good spot with the Raiders and the average annual value of his contract ($5 million) is in line with what some veteran quarterbacks are paid in backup roles. While with Cincinnati in 2015, he filled in for Andy Dalton, completing 66.4 percent of his passes with six touchdowns and two interceptions; McCarron also made one postseason start. He's a good reserve behind Derek Carr.
10. Trevor Siemian, Minnesota Vikings
Experience: Fourth NFL season, 24 career starts, 5,686 passing yards
Why he's here: There's a compelling case for the Vikings having the best roster in the NFL, factoring in the quarterback or when having a rest-of-the-roster conversation. So while the signing of Kirk Cousins is what will likely dictate how far this team goes in the playoffs, the trade for Siemian -- who started plenty over the past two years with Denver -- was an important fail-safe move, giving Minnesota a player who can start a pocket of games if needed and at least help to keep the offense functional.
Three-and-out: On the other side of the spectrum, here are three teams whose backup quarterback situations give us significant pause:
1. Alex Tanney, New York Giants
Experience: Has been with eight NFL teams
Why he's here: In a rather surprising move, the Giants ditched Davis Webb this preseason, a year after taking him in the third round (albeit under a different regime), opening the door for Tanney to back up Eli Manning. It's not exaggerating to say Tanney is most well-known for his trick-shot quarterback video than his NFL career. He has attempted just 10 passes in his career.
2. Taylor Heinicke, Carolina Panthers
Experience: Fourth NFL season
Why he's here: Heinicke has bounced around since entering the league as an undrafted free agent in 2015. The 25-year-old was regarded as a developmental arm for Minnesota before brief stints in New England and Houston. Now he's in Carolina behind Cam Newton, cementing the backup spot. Heinicke has taken as many sacks (one) as he has completed passes (one) in his career.
3. Cooper Rush, Dallas Cowboys
Experience: Second NFL season
Why he's here: The Cowboys have one of the youngest quarterback rooms in the league, with Dak Prescott in his third pro season serving as the elder statesman. Rush has not taken a meaningful snap in an NFL game and has just three passing attempts on his résumé. He currently serves as the backup ahead of Mike White, a 2018 draft pick.