The NFL is back. Here are the key storylines for the 2024 season.

The Chiefs will attempt to become the first team to win three straight Super Bowls. They will always have a chance as long as they have quarterback Patrick Mahomes and Coach Andy Reid. But there are challenges. Tight end Travis Kelce turns 35 in October. Wide receiver Rashee Rice faces criminal charges and possible NFL discipline related to his involvement in a six-vehicle crash on a Dallas expressway in March, although the league says it will wait until the legal process plays out before acting. Wideout Marquise Brown is plagued by a shoulder injury suffered during the preseason. A defense that did much of the heavy lifting last season now is without cornerback L’Jarius Sneed, who was traded to the Tennessee Titans in March.

The 49ers took the Chiefs to overtime in a memorable Super Bowl and still have a roster as talented as any. But the lead-up to the season was not exactly smooth. Wide receiver Brandon Aiyuk had a months-long contract-extension standoff with the team that resulted in a hold-in during training camp and weeks of trade deliberations before he agreed to a four-year, $120 million deal last week. Left tackle Trent Williams held out in a contract dispute before rejoining the team Tuesday. There was a harrowing near-tragedy when rookie wide receiver Ricky Pearsall was shot in the chest Saturday as the victim of a robbery attempt, according to authorities. He was released from a hospital Sunday. This could be the last go-round for this core group of standout players. Quarterback Brock Purdy will be eligible for a contract extension after this season, and the 49ers no longer will have the luxury of having him on a cheap rookie deal.

The Detroit Lions and Houston Texans were last season’s breakthrough teams. The Lions won the NFC North and had a 17-point lead in the NFC championship game before falling to the 49ers. The Texans won the AFC South and reached the divisional round of the playoffs with a brilliant rookie quarterback, C.J. Stroud, and a successful rookie head coach, DeMeco Ryans. What can those two teams do for an encore? This time, they must deal with the burden of expectations.

Rodgers did not play in any preseason games but resembled his old, four-time-MVP self — at least, the 40-year-old version of it — on the practice field. He lasted only four offensive snaps in his Jets debut last year before his season ended with a torn left Achilles’ tendon. If he can remain on the field, the Jets have enough other pieces on their sturdy defense and around Rodgers on their revamped offense to make things extremely interesting.

Three of the record-tying six quarterbacks chosen in the opening round of April’s draft — all within the first 12 picks — begin the season as starters: Caleb Williams with the Chicago Bears, Jayden Daniels with the Washington Commanders and Bo Nix with the Denver Broncos. Drake Maye waits his turn, for now, behind Jacoby Brissett with the New England Patriots. Michael Penix Jr. backs up Kirk Cousins in the Atlanta Falcons’ odd quarterback dynamic. J.J. McCarthy underwent surgery for a meniscus tear in his right knee suffered in the preseason opener, and his rookie season with the Minnesota Vikings ended before it really even started. It’s time to begin finding out whether this heralded quarterback class will live up to its billing.

Cousins left the Vikings to sign a four-year, $180 million deal with the Falcons in free agency. The Pittsburgh Steelers signed Russell Wilson after he was released by the Broncos and traded for Justin Fields. Steelers Coach Mike Tomlin is going with Wilson, who will attempt to recapture the success of his 10 seasons with the Seattle Seahawks after two turbulent seasons in Denver. Elsewhere, the Las Vegas Raiders chose newcomer Gardner Minshew II as their starter. Sam Darnold has the starting job in Minnesota with McCarthy sidelined. And Brissett is the starter, at least for the time being, in New England.

Coach Bill Belichick is gone, as the Patriots parted with him in January after 24 seasons and six Super Bowl triumphs. Quarterback Tom Brady is long gone. The Patriots have made only one playoff appearance in four seasons since his exit. It’s a new era for New England with Jerod Mayo as the coach and Maye as the would-be franchise quarterback in waiting. The expectations should be kept in check after last season’s 4-13 struggles.

The NFL made one of the most consequential rule changes in its history in March when team owners ratified the competition committee’s proposal for a new kickoff format. The preseason results were encouraging, with an improved return rate and no major injury issues. But now the games count, and it remains to be seen how teams will approach the revised kickoff. The league also banned hip-drop tackles over the objection of the NFL Players Association. That prohibition was not a significant factor during the preseason, with no penalties called by the on-field officials and only two infractions subsequently identified by the league, but it could be a talking point again during the season.

The league is expanding its use of instant replay as an officiating tool this season. The NFL will give replay officials an increased role in assisting the on-field officials with certain objective aspects of penalties for roughing the passer, intentional grounding and late hits out of bounds. But the league will not utilize its electronic system for measuring first downs, which it continued to test in the preseason, during this regular season. It could be considered for regular season use in 2025.

Jim Harbaugh is back in the NFL with the Los Angeles Chargers after taking Michigan to the College Football Playoff championship last season. He inherits a team with a franchise quarterback in Justin Herbert but also plenty of roster holes after Harbaugh and General Manager Joe Hortiz faced a salary cap crunch in the offseason. Harbaugh is a proven NFL winner, having led the 49ers to three appearances in the NFC championship game and a Super Bowl appearance during his four-year tenure as their coach. He presumably will get it done at some point in Los Angeles. Will that start this season?

Belichick is out of the league and will do broadcasting work this season. Pete Carroll and Mike Vrabel also failed to land head coaching jobs after being ousted following last season. Teams that falter in 2024 could have some big-name candidates to consider.

Brady’s work as an analyst for Fox will be closely scrutinized as he begins his broadcasting career, and there are complicating factors. His proposed deal for part-ownership of the Raiders remains pending before the NFL finance committee and must be approved by at least 24 of the 32 owners. That could occur as soon as October. The league will prohibit Brady, based on conflict-of-interest concerns, from participating in broadcast production meetings with NFL teams and from being in teams’ facilities to watch their practices or perform other activities, according to a person familiar with the matter.

The Buffalo Bills have won four straight AFC East titles. They have gotten as far as the AFC championship game. But they have yet to return to a Super Bowl during this run of prosperity with Josh Allen at quarterback, and they traded four-time Pro Bowl wideout Stefon Diggs to the Texans in April. Allen’s presence makes the Bills an annual contender. But it’s fair to wonder whether the roster around him remains of championship caliber.

Prominent quarterbacks continued to land lucrative contract extensions. The Jacksonville Jaguars’ Trevor Lawrence and the Packers’ Jordan Love signed extensions worth $55 million per season to match the Cincinnati Bengals’ Joe Burrow as the NFL’s highest-paid players. Tua Tagovailoa signed an extension with the Miami Dolphins worth $53.1 million per season. The notable exception to this point has been the Dallas Cowboys’ Dak Prescott, who is eligible for unrestricted free agency after this season.

Owner Jerry Jones did not fire Coach Mike McCarthy following the Cowboys’ stunning opening-round home playoff loss to the Packers. But he did not extend McCarthy’s contract, either. So McCarthy and Prescott are in the final season of their contracts. Wide receiver CeeDee Lamb held out in a contract dispute before agreeing to a four-year, $136 million extension, and star pass rusher Micah Parsons also is in line for an extension. Jones has declared the Cowboys “all in,” and they could jockey again with the Eagles for NFC East supremacy.

How many more 17-game regular seasons will the NFL have? Lloyd Howell, the NFLPA’s executive director, told The Washington Post in July that the union has begun high-level discussions with the NFL about the potential implementation of an 18-game regular season. It’s possible that the league and NFLPA could reach an agreement to put an 18-game season into effect before the expiration of their current labor deal after the 2030 season.