NFL play-offs: Patrick Mahomes, Josh Allen and Tom Brady aim for Super Bowl 57

Drama, excitement, sheer athleticism - the NFL showed again this season that it has it all.

Yet there was also a stark reminder of the risks involved with such a physical sport as American football.

Buffalo Bills safety Damar Hamlin suffered a cardiac arrest during the penultimate round of the regular season, sparking an outpouring of support from across the league.

As he continues to recover at home, emotions are still running high, particularly at Buffalo, as they prepare for the start of the play-offs this weekend.

Last season's Most Valuable Player Aaron Rodgers will not feature as his Green Bay Packers missed out on the final weekend of the regular season while this year's MVP favourite Patrick Mahomes earned a breather, with his Kansas City Chiefs the number one seed in the AFC.

But record seven-time Super Bowl winner Tom Brady is back again while a host of young quarterbacks are ready for their shot at glory and a spot in Super Bowl 57.

• Hamlin thanks fans for 'overwhelming love'

How do the NFL play-offs work?

This is the third season since the NFL expanded the number of teams progressing to the play-offs from 12 to 14, seven from each Conference.

The number of games on wildcard weekend increased from four to six, so now 12 games are played over three weeks to decide who will reach the Super Bowl.

Now only the top seed in each Conference earns a bye to week two of the play-offs, rather than the top two previously, and teams from each Conference are kept apart until the Super Bowl.

Seeds two to seven battle it out on what some NFL enthusiasts now call 'super wildcard weekend' as there are a whopping six knockout games played over three days.

The winners of each game then join the top seeds in the divisional round, and the four winners there meet in the Conference Championships, effectively the Super Bowl semi-finals as the two winners earn the right to represent their Conference in the big game.

This year it takes place at State Farm Stadium, home of the Arizona Cardinals, on 12 February, but there is a slight quirk with this season's play-offs.

Normally the highest seed remaining plays at home to the lowest seed throughout the play-offs.

However, if the Bills face the Chiefs in the AFC Championship game, it will be played at a neutral venue - namely Atlanta's Mercedes-Benz Stadium - because the game which was cancelled because of Hamlin's injury means Buffalo have one less on their record, which determines seedings.

Wildcard fixtures (away teams first, kick-offs in GMT)

• Seattle Seahawks at San Francisco 49ers (21:30 Saturday)

• Los Angeles Chargers at Jacksonville Jaguars (01:15 Sunday)

• Miami Dolphins at Buffalo Bills (18:00 Sunday)

• New York Giants at Minnesota Vikings (21:30 Sunday)

• Baltimore Ravens at Cincinnati Bengals (01:15 Monday)

• Dallas Cowboys at Tampa Bay Buccaneers (01:15 Tuesday)

Who are the favourites to win the Super Bowl?

The Chiefs are the slight favourites, with quarterback Mahomes looking to lead them to a third Super Bowl in four years.

Both they and the Philadelphia Eagles finished the regular season with a 14-3 record to clinch the top seeds - and a bye for the first week of the play-offs, giving Eagles quarterback Jalen Hurts a chance to rest the shoulder problem that kept him out for two games.

After a 6-3 start, the Bills showed why they began the season as Super Bowl favourites by winning their past seven and are now being carried by an emotional wave of support after the Damar Hamlin incident.

The Cincinnati Bengals, last year's Super Bowl runners-up, are also in good form having won their past eight while a mid-season trade for dual-threat running back Christian McCaffrey helped propel the San Francisco 49ers to a 10-game winning streak, despite their third-choice quarterback starting the past five.

Brock Purdy was this season's 'Mr Irrelevant', the man selected last in the NFL Draft, yet he is set to lead the 49ers into the play-offs after they lost Trey Lance and Jimmy Garoppolo to injury.

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Can Brady win an eighth Super Bowl ring?

Veteran quarterback Brady was retired for just 40 days before coming back for a 22nd season as a starter in the NFL.

And although he had his first losing season (8-9), it was enough for the Tampa Bay Buccaneers to win their division and maintain Brady's record of reaching the play-offs every year since 2002 (he was injured for 2008).

It has been a mixed year for the Bucs on both sides of the ball, with their offence not as dangerous as it was in Brady's first two seasons in Florida.

Yet the 45-year-old still set the NFL record for pass attempts in a season (733) and broke his own record for completions (490), and just two weeks ago threw for three touchdowns and a season-best 432 yards.

The Dallas Cowboys may have a better record (12-5) but in a knockout scenario, it is difficult to write off a man who already has 47 play-off games under his belt.

"Everything will be determined by what we do from here going forward," said Brady. "The team that advances is the team that plays the best that day, not the team that had the best record or the home field."

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Hamlin now recovering at home but Tagovailoa ruled out

After a mixed start, the Bills had regrouped and were ending the regular season strongly when it seemed disaster had struck during their penultimate game.

Hamlin collapsed after making a tackle against the Bengals on 2 January and suffered a cardiac arrest, but his heartbeat was restored on the field.

With Hamlin watching from his hospital bed, the Bills produced a stirring display to beat the New England Patriots last Sunday, with running back Nyheim Hines scoring from the very first play since Hamlin's collapse with a kick-off return.

Hamlin was discharged from hospital on Wednesday and Bills coach Sean McDermott said it is up to him when he returns to the team facilities, adding that the safety and his father Mario want the players and staff to focus on Sunday's game with the Miami Dolphins.

"They want us to go do our job, and that's what we've got to do," said McDermott.

Miami are set to be without Tua Tagovailoa as he remains in the NFL's concussion protocol, which was revised after the quarterback was also concussed in September.

The 24-year-old had been cleared to play despite appearing to suffer a concussion just four days earlier in the Dolphins' defeat by the Bills.

Miami have limped into the play-offs, losing five of their last six, and there are now concerns over Tagovailoa's NFL future after suffering two diagnosed concussions in the same season.

• NFL play-off schedule & BBC coverage plans

What else to look out for

It wasn't long ago that Mahomes was the most exciting young talent in the NFL. Yet remarkably, at the age of 27, the 2018 MVP will be the oldest AFC quarterback in this year's play-offs.

Mahomes versus Allen looked set to be a rivalry for years to come in the AFC after the pair produced an epic shootout in last season's divisional round.

But Joe Burrow showed that he will be in the mix by upstaging Mahomes in the Championship Game to lead the Bengals to a surprise Super Bowl appearance last year - and they are back in the play-offs this season.

Burrow and Trevor Lawrence were the number one draft picks in 2020 and 2021, and both have helped turn around their team's fortunes as this year Lawrence has led the Jacksonville Jaguars into the post-season for the first time in five years.

This weekend Lawrence will be up against the Los Angeles Chargers and Justin Herbert, who will also be making his first play-off appearance after the Chargers narrowly missed out last year.

Lamar Jackson, the 2019 MVP, is another of the exciting AFC quarterbacks but he is struggling with a knee injury so Tyler Huntley could continue to fill in for the Baltimore Ravens at Cincinnati.

In the NFC, the New York Giants have ended a six-year play-off drought and the Seattle Seahawks are making an unexpected appearance.

They were tipped to have one of the worst records in the NFL this season after quarterback Russell Wilson was traded to Denver but his replacement Geno Smith, 32, has defied the odds in his first season as a regular starter since 2014.

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