As another NFL regular season begins, unbridled optimism is once again at its peak throughout the league. But by Tuesday morning, 16 teams will be dealing with the fallout of a loss, leaving their fans wondering whether the opening defeat was a mere setback or cause for recalibrating expectations.

A spotty start doesn't have to incite panic, of course. Plenty of contenders have started their seasons on the wrong foot in recent years, including the two-time defending champion Kansas City Chiefs getting tripped up by the Detroit Lions in last season's opener and the Buffalo Bills falling short against the New York Jets in overtime. But while early troubles aren't necessarily a death knell for a season, they inevitably put a team in a hole that can be difficult to escape.

With that in mind, we asked USA TODAY Sports' NFL staff: Which NFL team is at risk of stumbling out of the gates? Their answers – two writers had the same one – are below.

Buffalo Bills

The Buffalo Bills. And not just because they may still be hung over after being eliminated from the playoffs on their own turf by the Kansas City Chiefs. The schedule-maker was not friendly to Josh Allen and Co., as Buffalo hits the road for four of its first six games – and all four of those matchups are against legitimate contenders in Miami, Baltimore, Houston and the Aaron Rodgers-infused New York Jets. And the Week 3 home game against Jacksonville is hardly a gimme. The Bills will be tested as harshly as any team in the league in the early weeks. Survive that gauntlet and they'll solidify themselves as the team to beat again in a very competitive AFC East. But an early tailspin could wreak havoc on their designs (still) of finally getting over the hump and emerging as a Super Bowl team...as coach Sean McDermott has promised. Hey, it's too early for a must-win game, but with what's ahead in the next few weeks, the Bills better not sleep on the opener against Kyler Murray and the Arizona Cardinals.

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— Jarrett Bell

The Bills open up against a rebuilding Arizona club. Buffalo should stampede over the Cardinals in Week 1. Josh Allen has a 20-6 career record against NFC opponents. But then the Bills enter a daunting five-game AFC stretch with four contests on the road: at Miami, Jaguars, at Ravens, at Texans and at Jets. It’s likely the Bills will be underdogs in all four road games. I predict Buffalo will limp into Week 7 with a losing record. It doesn’t help matters that Buffalo went through an extreme makeover during the offseason on both sides of the football, losing established starters such as wide receiver Stefon Diggs, center Mitch Morse and safeties Jordan Poyer and Micah Hyde. The beginning of the season is going to be a transition period for Bills, and they very well could stumble along the way.

— Tyler Dragon

San Francisco 49ers

Good luck finding a team with more talent than the reigning NFC champion San Francisco 49ers. But will it all be pulling in the same direction out of the chute? The first-team offense looked rather disjointed during its preseason cameos, when “hold in” WR Brandon Aiyuk was in non-approved sideline street apparel and holdout LT Trent Williams was nowhere to be found. Both are back in the fold now with the financial remedies they’d been seeking. But they’re trying to reassimilate after more than a month of missed practice reps. Elsewhere, S Talanoa Hufanga, LB Dre Greenlaw, G Jon Feliciano and CB Ambry Thomas are all in various stages of injury rehab. The Niners, who have failed to reach the NFC championship game just once in the past five seasons, should ultimately be fine … but don’t be surprised if they’re not firing on all cylinders until October.

Green Bay Packers

The Packers are the sexy Super Bowl pick in the NFC and by the end of the postseason, they will be playing for the right to represent the conference in New Orleans. Out of the gate, however, the Pack will follow a playbook Cheeseheads have become all too familiar with over the years. Green Bay lost to the Pittsburgh Steelers on the road in Week 8 last season to fall to 2-5. Then quarterback Jordan Love played at a MVP level for the second half of the season. The Packers assumed the No. 7 seed and knocked off the Dallas Cowboys on the road in the wild-card round before being a play or two away from doing the same to the San Francisco 49ers. The Packers’ schedule is manageable to start, but the Indianapolis Colts come to Lambeau Field Week 2 after the international opener against the Eagles in Brazil. But the late-season wins will be worth whatever early-season disappointment the green and gold may suffer.

— Chris Bumbaca

Los Angeles Rams

Sean McVay's crew floundered to a 3-6 start last season before winning six of their last seven contests to claim a wild-card berth. That group, however, was unburdened by lofty expectations in what admittedly was supposed to be a transitional year for the franchise. This year, there's ample reason to believe that the Rams have the proper make-up to return to the postsesaon.

Still, there are several factors that could signal more early-season struggles. The offensive line hardly seems settled, with starting left tackle Alaric Jackson serving a two-game suspension, right tackle Rob Havenstein hobbled by an ankle injury and Steve Avila and Jonah Jackson flipping positions at left guard and center. A new defensive coordinator in Chris Shula takes over Raheem Morris' old unit, and he'll be tasked with keeping together thin groups in the secondary and at inside linebacker. And then there's that little matter of forging on without three-time Defensive Player of the Year Aaron Donald and his singular force in the pass rush.

Those issues can be navigated over the course of the season, but it might be asking a little much of Matthew Stafford to overcome them in the first week. The Detroit Lions (Week 1) and San Francisco 49ers (Week 3) have both the offensive firepower and tenacity along the lines to throw the Rams off their game, while the Arizona Cardinals loom as an upset threat in between those two matchups. Don't be surprised if Los Angeles doesn't find its top form until after the first month or so.

— Michael Middlehurst-Schwartz