A starting quarterback gets hurt and a backup steps in. It happens every year in the NFL in a half-dozen cities or more.
It has happened this season in Miami and Green Bay and Houston and Indianapolis and Minnesota and Arizona. Sunday, it happened to the Eagles.
In a league that perpetually seems to suffer from a shortage of competent quarterbacks, having your starter go down usually is a knife to the heart.
It has been for most of the teams mentioned above. Will it be for the Eagles? We'll see.
Nick Foles might not be Carson Wentz, but he isn't Brett Hundley or Tom Savage or Blaine Gabbert, either. He's a guy with a resume that includes 36 career starts, a .555 win percentage, 56 career touchdowns, a Pro Bowl MVP award, and that magic carpet ride in 2013 when he threw 27 touchdown passes and just two interceptions and guided the Eagles to their most recent playoff appearance.
"That was just a surreal year,'' Foles said. "We just all played well together. It was a chemistry thing. That's something that's so often overlooked in this game – the dynamics of the locker room. The key is getting into a rhythm. We got into a rhythm.''
When Chip Kelly was hired as Andy Reid's replacement after the Eagles' 4-12 season, many thought Foles was a dead man walking. Foles is a pocket passer with limited mobility and didn't seem to be a particularly good fit for the zone-read, no-huddle offense Kelly ran at Oregon.
"Chip did a very good job of adapting the offense to whoever was going to be in there [at quarterback],'' said Evan Mathis, the starting left guard on that 2013 team. "There were still plays where Nick would pull the ball and run. But things were designed with that in mind. Whether it was Nick, or whether it was Mike [Vick] back there.''
Kelly had an open competition for the starting quarterback job, and Vick was declared the winner after completing 73.7 percent of his passes and averaging 10.1 yards per attempt in the preseason.
The Eagles lost three of their first four games with Vick as the starter. After Vick injured his hamstring against the Giants in Week 5, Foles took over and started 10 games (he missed one with a concussion). The Eagles were 8-2 in his 10 starts.
Foles had a lot of help, including one of the league's best running backs, LeSean McCoy, who would lead the league in rushing that year with 1,607 yards, and one of the league's most dangerous vertical threats, DeSean Jackson. Foles averaged just 28.7 pass attempts in his 10 starts and threw more than 34 passes just once.
He also had an offensive line that not only was very good but also managed to stay incredibly healthy. None of the five starters missed a start in 2013.
"That was pure luck,'' Mathis said. "There are so many injuries in this league. Especially in the trenches. When you have all five guys start every game, you're able to build chemistry. And that was a pretty damn good offensive line across the board.''
Foles' 119.2 passer rating that season is the third highest in league history, behind only Aaron Rodgers' 122.5 in 2011 and Peyton Manning's 121.1 in 2004.
His 0.63 percent interception rate (two in 317 pass attempts) was the third lowest in league history.
Foles had a 69.6 percent red-zone completion rate, even better than Wentz's 64.9 this season. He had a league-best 130.9 passer rating against the blitz and was the league's top deep-ball passer, completing 45.4 percent of his throws of 20 yards or more.
"Everybody acts like Nick Foles hasn't been a great quarterback in this league before,'' center Jason Kelce said. "He's got a set of cleats in the Hall of Fame for throwing the most touchdown passes in a single game. He's been pretty darn good in Philadelphia before.''
Canton requested his cleats after he threw seven touchdown passes in a 49-20 road win over the Raiders in Week 9 that turned the Eagles' season around. The seven TDs tied the NFL single-game record.
"It was like playing a video game on the lowest difficulty setting,'' Mathis said. "I'm not saying it was that easy to do, but that's the way it feels when things really go your way like that.
"We were 3-5 going into that game. If we had lost, we would've dropped to 3-6. That would've been a tough hole to climb out of. That game helped give us a lot of confidence in what we had the ability to do when we were executing.''
The Eagles won seven of their last eight and clinched the NFC East title in Week 17 in Dallas, beating the Cowboys, 24-22, and avenging an earlier 17-3 loss. Foles completed 17 of 26 passes for 263 yards, with two touchdown passes and no interceptions in the win.
"We just had a totally different mentality going into that second Dallas game,'' Mathis said. "We were very lethargic the first time we played them. We just weren't all there. We weren't clicking.
"The second time around, we were a different team. Shady [McCoy] was chasing the rushing title, Nick was on fire, and we were focused on getting where we wanted to be.''
The season came to an abrupt and disappointing end the next week when the Eagles lost to New Orleans in the first round of the playoffs, 26-24, on a field goal with no time left.
Foles played well against the Saints, completing 23 of 33 passes for 195 yards and two touchdowns. But a 39-yard kickoff return by future Eagle Darren Sproles and a dumb horse-collar penalty on Cary Williams helped the Saints get close enough for a game-winning field goal by Shayne Graham.
"We kind of caught the league off-guard for sure with the offense we were running,'' Kelce said, referring to Kelly's zone-based no-huddle. "But Nick just had an unbelievable year. He made some great throws. We had some great skill players.''
Said Mathis: "It's still frustrating to think about what we could've done and what we should've done that year. To see [Foles] so young perform as well as he did was exciting. We had very high hopes for him, very high hopes for the whole team under Chip. Things were only supposed to get better.
"Seasons like 2013 still happen. They're still a great memory and something to talk about.''
And if you're an Eagles fan hoping that your team's Super Bowl hopes didn't die when Wentz's ACL snapped Sunday, something to maybe believe in.