First, Patrick Mahomes went down. Then, it was Micah Parsons.

The NFL lost two of its all-time greatest players to serious knee injuries in a span of a few hours on Sunday, ruining a day filled with exciting comebacks and fascinating stories.

Forty-four-year-old Philip Rivers played his first game in 1,800 days, and nearly led the 14-point underdog Indianapolis Colts to a stunning upset against Seattle, before Jason Myers kicked a 56-yard field goal with 29 seconds left to lift the Seahawks to an 18-16 victory.

Reigning NFL MVP Josh Allen led the Buffalo Bills from a 21-0 deficit to a 35-31 victory at New England, snapping the Patriots' 10-game winning streak and preventing them from clinching the AFC East title.

Rookie quarterback Tyler Shough rallied the New Orleans Saints to a 20-17 comeback victory over the Panthers, capped by Charlie Smyth's 47-yarder as time expired, damaging Carolina's chances to win the NFC South and boosting Tampa Bay's hopes.

Matthew Stafford and the Los Angeles Rams overcame a 10-point deficit and rolled past the Lions 41-34, dampening Detroit's playoff bid. The Rams lost three-time All-Pro wide receiver Davante Adams to a hamstring injury in the game. He could miss Thursday night's game at Seattle, a battle for first place in the NFC West.

Jalen Hurts played like the Super Bowl MVP, and the Philadelphia Eagles snapped a three-game losing streak with a 31-0 rout over the woeful Las Vegas Raiders.

But the injuries to Mahomes and Parsons overshadowed everything else that happened in Week 15.

Even the Chiefs being eliminated from playoff contention was secondary to the news about Mahomes.

The three-time Super Bowl MVP tore the ACL in his left knee late in the fourth quarter of a 16-13 loss to the Los Angeles Chargers that ended Kansas City's streak of 10 straight playoff appearances and seven consecutive trips to the AFC championship game.

"Don't know why this had to happen," Mahomes posted on social media before the diagnosis was announced. "And not going to lie, it hurts. But all we can do now is trust in God and attack every single day over and over again. Thank you Chiefs kingdom for always supporting me ... I will be back stronger than ever."

Parsons is believed to have suffered a torn ACL in his left knee, a person with knowledge of the All-Pro pass rusher's injury told reporters on Sunday.

The person spoke on condition of anonymity because the severity of the injury hadn't been confirmed by tests.

"I'm sickened," Parsons told reporters in a text message.

Parsons' injury is a devastating blow to the Green Bay Packers, who lost 34-26 to Denver on Sunday to fall a half-game behind the NFC North-leading Chicago Bears.

Parsons was steps away from another sack when he suddenly pulled up and fell to the ground, grabbing at his left knee.

Asked about the possibility that Parsons tore his ACL, coach Matt LaFleur responded: "It doesn't look good. I'll leave it at that."

With Parsons, the Packers were Super Bowl contenders. Without him, it'll be much more difficult to get there. The Packers take on the Bears in a showdown for first place on Saturday night.

"We all know what type of player he is, and the impact he's had on our football team, and to lose somebody like that, it's tough," LaFleur said."Like I said, nobody's going to feel sorry for us. We've got to find a way, and guys have got to rally around one another."

Mahomes and Parsons will not only miss the rest of this season, but their status for the start of 2026 is uncertain. Players typically return from ACL injuries in 9-12 months.

Running back Adrian Peterson tore the ACL and MCL in his left knee on Dec 24, 2011. He was back on the field for Week 1 the next season, ran for 2,097 yards in 16 games and became the last non-quarterback to win the NFL MVP award in one of the most remarkable comebacks in league history.

Quarterback Carson Wentz tore his ACL, LCL and sustained damage to his IT band and meniscus on Dec 17, 2017 and ended up watching the Eagles win their first Super Bowl in franchise history from the sideline. He returned to the starting lineup in Week 3 the following season, and threw for 3,074 yards, 21 touchdowns, seven interceptions and a 102.2 passer rating in 11 games.

If Mahomes and Parsons didn't damage other ligaments, it increases the possibility they could return for the 2026 season opener.

Regardless, both star players have a long, grueling rehab ahead.

Agencies Via Xinhua