The first week of the NFL season is a roller coaster. After the second, there is still too little data to know which teams are contenders and which ones are not. By the third, trends begin to form.

But Week 4?

That’s enough time for separation in the standings to reveal the surprises — who might stick around, and which preseason favorites might be in trouble.

Week 4 of the 2024 season arrives this weekend with five undefeated teams remaining — Buffalo, Pittsburgh and Kansas City in the AFC, and Minnesota and Seattle in the NFC. Meanwhile, Tennessee, Jacksonville and Cincinnati are still searching for their first win.

Here’s what we will be watching for in each of the weekend’s games:

Vikings (3-0) vs. Packers (2-1)

No one would have picked preseason backups Sam Darnold and Malik Willis to be a combined 5-0 at this point, a result that is a testament to their adaptability playing in new offenses.

Yet this week is both QBs’ biggest challenge yet. Willis will have to outsmart a Vikings defense that has harassed its opponents enough to rank, as gauged by advanced stats, as the league’s best.

On the other side, Darnold will face a Green Bay defense that has produced nine league-best takeaways.

Jaguars (0-3) at Texans (2-1)

Only New England and Miami have scored fewer points than the anemic 13.3 Jacksonville has averaged so far. Houston could put this game away early, as long as its offensive line keeps C.J. Stroud upright (11 sacks) and its running game finally finds its footing.

Rams (1-2) at Bears (1-2)

Chicago spent the offseason putting weapons around the quarterback and No. 1 overall pick Caleb Williams. Nearly a month into the season, however, the question is whether it can protect him.

Williams has been sacked 13 times, tied for the NFL’s third-highest total. Yet this could be the break the Bears need. Only Tampa Bay and Atlanta have recorded fewer sacks than the Rams (four), who are struggling to find a pass rusher after future Hall of Famer Aaron Donald retired.

Bengals (0-3) at Panthers (1-2)

All that is certain is that at least one team will leave happy following the misery that has started each of their seasons. Panthers quarterback Andy Dalton will look for revenge against his former team.

Eagles (2-1) at Bucs (2-1)

This is a litmus-test game. Eagles coach Nick Sirianni, having already endured an offseason full of questions about his coaching, has faced another round of criticism after his fourth-down decision-making.

Tampa, meanwhile, started 2-0 only to suffer a 19-point home loss to Denver that coach Todd Bowles described as a “complete team collapse.” Take note of how Tampa attempts to contain Jalen Hurts; the Bucs are the only defense yet to allow a passing touchdown.

Chiefs (3-0) at Chargers (2-1)

These are two teams both dealing with uncertainty around their offensive pillars. Chargers quarterback Justin Herbert has said he is doing everything possible to play after reaggravating a high-ankle sprain last week, but has been limited in practice.

While the Chiefs’ offense remains dangerous thanks to coach Andy Reid’s ability to plug in new faces around quarterback Patrick Mahomes, it hasn’t featured much of Mahomes’ top collaborator, tight end Travis Kelce. It’s not only Kelce’s eight catches that are surprising, but the fact he has been targeted only 12 times.

Saints (2-1) at Falcons (1-2)

Which Saints offense will show up — the one that hung up more than 40 points in back-to-back weeks to start the season? Or the one that could only muster 12 against the Philadelphia Eagles?

Meanwhile, the Falcons’ 1-2 record doesn’t tell the full story. Their comeback win over the Eagles was impressive, and they hung tough with the Kansas City Chiefs in a close loss. This is an early key matchup in the NFC South.

Broncos (1-2) at Jets (2-1)

This is the Nathaniel Hackett revenge game!

Sean Payton was not kind to the former Broncos coach after he took over the job. Hackett is now Aaron Rodgers’ handpicked offensive coordinator with the New York Jets, and Rodgers surely remembers what Payton had to say about his coach.

Steelers (3-0) at Colts (1-2)

This is another chance for Justin Fields to solidify his grip on the Steelers’ starting quarterback job. Fields is 3-0 filling in for Russell Wilson, and has played steady, solid, mistake-free football. If Fields wins again, could Pittsburgh really hand the job back to Wilson?

Commanders (2-1) at Cardinals (1-2)

All eyes will and should be on rookie quarterback Jayden Daniels, who led the Commanders to a stunning upset over the Bengals last week on “Monday Night Football.”

Daniels entered this season with less hype or interest than his fellow first-round quarterbacks, but he’s been the best of the bunch. The Cardinals, meanwhile, are 1-2 and desperate for a win, as the Packers and 49ers loom on the schedule.

Patriots (1-2) at 49ers (1-2)

The 49ers have lost two games in a row and remain without star running back Christian McCaffrey. This is another test for Brock Purdy to see if he can lead the San Francisco offense to success without its best player.

Browns (1-2) at Raiders (1-2)

Deshaun Watson has been one of the worst quarterbacks in the league this season (he’s ranked 30th in ESPN’s QBR), while the Raiders have already hinted at making a switch at the position. If you want to watch two struggling offenses, then this is the game for you.

Bills (3-0) at Ravens (1-2)

Again, this is only Week 4 — and yet, Sunday’s prime-time matchup feels like one that could be repeated in the playoffs. Behind quarterback Josh Allen’s marked improvement at eschewing turnovers — zero interceptions — the Bills (3-0) have outscored opponents by 64 points, the league’s best scoring differential. Despite a head-scratching loss to Las Vegas, Baltimore and Lamar Jackson still own what advanced statistics rank as the second-best offense in the league behind only, yes, Buffalo.