On Thursday, Nick Foles -- one of the best backup quarterbacks ever -- officially retired after 11 NFL seasons. Foles, of course, led the Eagles to a victory in Super Bowl 52 in one of the more amazing stories in NFL history.

And that got me thinking.

With Foles calling it quits, who are some of the other more noteworthy backup quarterbacks in NFL history? Which passers came in during an emergency and often used their experience and savvy to thrive in an unexpected way? There's a long list of quality backup quarterback starts, but only a few veterans really stand out for having extended careers as the No. 2.

Let's take a look below and see who stands on top as the greatest quarterback understudy in league history. The only parameter to keep in mind is that I featured quarterbacks who were primarily known for being backups. Guys like Tom Brady and Kurt Warner -- who started in the NFL as backups only to become Hall of Fame starters -- need not apply at all.

8. Brian Hoyer

Notable teams: New England Patriots (2009-2011, 2017-2018, 2020-2022), Cleveland Browns (2013-2014)

Career stats: 79 games played, 10,999 passing yards, 59.3 completion percentage, 53 touchdown passes, 37 interceptions

A former undrafted free agent, Hoyer has carved out an extended career on the basis of professionalism and his being a steady hand. In addition to his general effectiveness in spot duty, Hoyer has been a valuable mentor to several young quarterbacks. He's a testament to making the most out of an extended career despite never being The Guy.

7. Teddy Bridgewater

Notable teams: Minnesota Vikings (2014-2017), New Orleans Saints (2018-2019), Miami Dolphins (2022)

Career stats: 79 games played, 15,120 passing yards, 66.4 completion percentage, 75 touchdown passes, 47 interceptions

Known for his famous two-glove look, Teddy "Two Gloves" Bridgewater actually began his career as a capable starter for the Vikings. But a devastating torn ACL suffered near the end of Bridgewater's Minnesota tenure would eventually turn him into one of the league's top backups. From this perspective, he was a perfect fit. He filled in admirably for Drew Brees at times towards the end of his run in New Orleans and bounced around various teams like the Dolphins and even Detroit Lions, helping playoff contenders stay afloat.

Most importantly, Bridgewater was always a cool customer. He often showed off his starting experience as someone who could seldom really be rattled by a defense.

6. Josh McCown

Notable teams: Chicago Bears (2011-2013), Cleveland Browns (2015-2016), New York Jets (2017-2018)

Career stats: 102 games played, 17,731 passing yards, 60.2 completion percentage, 98 touchdown passes, 82 interceptions

A quintessential journeyman, McCown collected contracts from different NFL teams throughout his career, like Thanos gathered up Infinity Stones. The oft-capable veteran bounced around nine different organizations over 16 seasons. His most noteworthy stints came with the Bears, in relief of Jay Cutler, with the Browns as a temporary starter/fill-in, and with the Jets as a mentor and backup to a younger Sam Darnold. These days, McCown is a quarterback coach with the Vikings. He's clearly using the mentor skills he gained as a backup to great advantage in his coaching career.

5. Ryan Fitzpatrick

Notable teams: Buffalo Bills (2009-2012), New York Jets (2015-2016), Tampa Bay Buccaneers (2017-2018), Miami Dolphins (2019-2020)

Career stats: 166 games played, 34,990 passing yards, 60.7 completion percentage, 223 touchdown passes, 169 interceptions

No one straddled the line of starter to backup quite like Fitzpatrick. Never good enough to take the complete reins of a team, Fitzpatrick's NFL career was littered with astonishing 3-4 game bursts of prolific passing. In 2018, while with the Buccaneers, Fitzpatrick became the first NFL quarterback to ever throw for at least 400 yards in three consecutive games. In a testament to his passing ability, Fitzpatrick has the career most passing yards and touchdowns for a quarterback without a single playoff appearance.

4. Doug Flutie

Notable teams: Chicago Bears (1986-1987), New England Patriots (1987-1989), Buffalo Bills (1998-2000)

Career stats: 92 games played, 14,715 passing yards, 54.7 completion percentage, 86 touchdown passes, 68 interceptions

Flutie had anything but a conventional pro football career. He began his NFL life trying to impress the Bears and Patriots. When he saw there was nothing for him stateside, Flutie spent most of the ensuing 1990s in the CFL, winning three different Grey Cups. When he came back to the NFL with Buffalo in 1998, Flutie surprisingly led the Bills to moderate playoff success. He ended up playing until he was 43 years old, fittingly capping one of the more bizarre lives in football.

3. Earl Morrall

Notable teams: Baltimore Colts (1968-1971), Miami Dolphins (1972-1976)

Career stats: 255 games played, 20,809 passing yards, 51.3 completion percentage, 161 touchdown passes, 148 interceptions

Another consummate professional, Morrall enjoyed a lengthy NFL career, but he didn't rise to true prominence until a stint with the Dolphins near the end. With Miami starter Bob Griese injured in 1972, Morrall stepped in and kept the Dolphins on track toward the only undefeated season to date before winning Super Bowl 7.

2. Frank Reich

Notable teams: Buffalo Bills (1985-1994)

Career stats: 118 games played, 6,075 passing yards, 54.5 completion percentage, 40 touchdown passes, 36 interceptions

Reich was never going to be the leader in Buffalo as long as Jim Kelly was the starter. But for a moment in 1993, he was unequivocally the story. Down by 32 points to the Houston Oilers in the AFC Wild Card Game, Kelly led the Bills to one of the biggest comeback wins in NFL history, stunning Houston 41-38 in overtime. Reich was marvelous in the victory, throwing for 289 yards and four touchdowns. That game and that result earned Reich enough goodwill to become a respected elder statesman through the rest of his career.

1. Nick Foles

Notable teams: Philadelphia Eagles (2012-2014, 2017-2018), Chicago Bears (2020-2021)

Career stats: 71 games played, 14,227 passing yards, 62.4 completion percentage, 82 touchdown passes, 47 interceptions

Was there any doubt who would top this list?

After briefly fading into irrelevance during the middle of his NFL career, Foles filled in for an injured Carson Wentz on the 2017 Eagles. He more than kept juggernaut Philadelphia afloat, eventually leading the Eagles to a win in Super Bowl 52 in a legendary performance where he threw for 373 yards and three touchdowns. He was also famously on the receiving end of the "Philly Special."

Foles parlayed that championship success into short, successful stints with the Jaguars, Bears, and Colts at the end of his career. But he is undoubtedly best known as a Philadelphia sports icon who brought the Eagles their first Super Bowl.

This article originally appeared on For The Win: The 8 greatest backup quarterbacks of all time, in honor of Nick Foles as he retires