The 32 things we learned from Week 4 of the 2023 NFL season:

1. A warm welcome back to Buffalo Bills S Damar Hamlin, who played in his first-regular season game since his terrifying cardiac episode at Cincinnati in January. He didn’t register in the box score, mostly playing special teams in Sunday’s win over the Miami Dolphins, but great to see him back in action – and in front of Bills Mafia at Highmark Stadium.

2. Who’s the league’s best team? The Philadelphia Eagles are 4-0 for the second straight season after surviving the Washington Commanders 34-31 in overtime.

2a. Philly QB Jalen Hurts improved to 21-1 over his past 22 regular-season starts going back to the 2021 season.

3. And strong case from the Bills (3-1), who moved into first place in the AFC East by embarrassing the previously unbeaten Dolphins 48-20 in what had been a highly anticipated matchup.

NFL STATS CENTRAL: The latest NFL scores, schedules, odds, stats and more.

3a. During its three-game winning streak, Buffalo’s average margin of victory has been 30 points.

4. While Miami entered the weekend with the league’s best offense, Buffalo’s overall balance – including the NFL’s No. 2 defense through three weeks – could be the differentiating factor between teams that could be on a playoff collision course for the second straight year.

5. Despite the setback, Miami rookie RB De’Von Achane had another big day, notching a pair of TDs a week after posting four. He becomes the fourth player in league history with six TDs in his first three career games and the fourth rookie since the 1970 AFL-NFL merger with six over a two-game span.

6. And even though they were outclassed, the Dolphins still claimed a bit of history. They became the third team to surpass 2,000 yards of total offense after four games, their 2,044-yard total the most ever.

7. But back to that best team question? It’s the San Francisco 49ers (4-0), the only unbeaten team west of Philadelphia. Since the start of Week 1, the Niners have been atop our power rankings – where they will remain this week.

7a. San Francisco won its 14th straight in the regular season.

8. And 49ers RB Christian McCaffrey is starting to put together an MVP dossier, his career-best four-TD performance extending his streak of games (playoffs included) finding the end zone to 13 – breaking Hall of Famer Jerry Rice’s team record.

8a. McCaffrey also had 171 yards from scrimmage in San Francisco's 35-16 beatdown of the Arizona Cardinals.

9. Who’s the league’s worst team? The Carolina Panthers fell to 0-4, pretty much handing the error-prone Minnesota Vikings their first victory thanks to a crucial strip sack – the Vikes returned rookie QB Bryce Young’s fumble for the go-ahead TD in the third quarter – and another lifeless offensive performance (232 yards).

10. But the correct answer is the Chicago Bears, who dropped to 0-4 and extended their franchise-worst losing streak to 14 games. Sunday was ugly. Chicago gave up 24 unanswered second-half points in its 31-28 loss to the Denver Broncos, who notched their first win under head coach Sean Payton.

10a. And as much deserved heat as QB Justin Fields has taken – he had a strong showing Sunday (career-high 335 yards and 4 TDs passing) – this loss will land at the feet of Matt Eberflus. The second-year coach eschewed what would have been a go-ahead field-goal attempt from about 36 yards with less than three minutes to play and instead watched his team fail to convert a fourth-and-1, Denver subsequently driving for what would be the game-winning three-pointer.

11. During the Super Bowl era (since 1966), 164 teams have started 0-4. One has reached postseason.

12. Not sure if you'd heard the rumors, but guess who showed up at the Jets-Chiefs game Sunday night? Yup, one of the hugest superstars in the NFL's orbit.

13. New England Patriots coach Bill Belichick’s first attempt to win his 300th regular-season game ended with the worst loss of his head coaching career, the Dallas Cowboys romping to a 38-3 victory.

13a. Not the Texas homecoming Pats RB Ezekiel Elliott wanted, either.

14. Prematurely anointed Offensive Rookie of the Year? Maybe Atlanta Falcons RB Bijan Robinson, who’s averaging 113 yards from scrimmage per game after a 137-yard effort in Sunday’s loss to Jacksonville.

15. Prematurely anointed Offensive Rookie of the Year? Maybe Houston Texans QB C.J. Stroud, whose 1,212 passing yards are second most among first-year players behind Cam Newon (1,386) in 2011.

16. But the prematurely anointed Offensive Rookie of the Year has to be Los Angeles Rams WR Puka Nacua, who scored his first NFL touchdown Sunday – a 22-yard catch-and-run from hobbled QB Matthew Stafford in overtime that salvaged a 29-23 win for LA at Indianapolis.

16a. Prior to the big score, Nacua ran his season totals to 39 catches for 501 yards, both marks the best ever by a rookie through four games.

17. The Cleveland Browns’ Dorian Thompson-Robinson and Las Vegas Raiders’ Aidan O'Connell became the fourth and fifth rookie quarterbacks, respectively, to start in 2023, their teams’ starters unable to post Sunday due to injuries suffered in Week 3. It didn’t go well for the freshmen, Thompson-Robinson and O'Connell each suffering losses while combining for six turnovers and 11 sacks taken.

18. Back to that Jets game ... did you notice that one of the owners of AFC Wrexham – the Welsh football (soccer) equivalent of the Jets – also showed up?

19. Defensive player of the week? Hand it to Los Angeles Chargers OLB Khalil Mack, who had the sixth game with at least six sacks since it became an official statistic in 1982. Mack also joined Hall of Famer Derrick Thomas as the only players with multiple games of at least five QB takedowns.

20. Toughest player of the week? Chargers QB Justin Herbert, who threw a 51-yard completion to secure Sunday’s 24-17 win over the Raiders despite playing the latter stages of the game with his non-throwing hand heavily wrapped and his middle finger splinted after he was hurt near the end of the third quarter during the runback of an interception he’d thrown.

21. With his brother, Pittsburgh Steelers star T.J. Watt, on hand, J.J. Watt was inducted into the Texans’ ring of honor Sunday. The greatest player in the franchise’s 22-season history, J.J. Watt was a three-time Defensive Player of the Year during his decade in Houston. The Texans marked the day by winning their first home game since 2021.

22. Ohi-whoa. A week after losing to the Browns 27-3, the Tennessee Titans beat the Cincinnati Bengals 27-3.

22a. Cincy’s 1-3 start is the worst of the Joe Burrow era, which began in 2020. He’s been on the losing end of his first October start each of the past three seasons.

23. Sunday night’s game against the Jets was Kansas City Chiefs QB Patrick Mahomes’ first NFL appearance in the New York market.

23a. Mahomes commemorated the occasion by tossing his 200th career TD pass, becoming the fastest player (84 games) ever to hit that milestone. He did not throw it to that Kelce guy.

24. 49ers WR Deebo Samuel was targeted zero times Sunday. He did carry the ball three times for 6 yards.

25. Sunday’s game was the 25th staged at London’s Wembley Stadium during the regular season since the league’s International Series began in 2007.

26. The Jaguars have played a league-most 10 regular-season games in London, twice the amount of any other team, and improved their record there to 5-5 with Sunday’s defeat of Atlanta. The Jags will play their 11th next weekend at Tottenham Hotspur Stadium against Buffalo.

27. Falcons WR Drake London scored his team’s only points in Sunday’s loss. Good nugget from Elias Sports Bureau and ESPN as London became the sixth player to score a TD in a city that shares his surname.

28. Also in first place? How about the Tampa Buccaneers, whose surprising 3-1 mark has them alone atop the NFC South following Sunday’s 26-9 win at New Orleans.

29. The Saints not only dropped their third in a row to the Bucs, they surrendered more than 20 points after keeping their previous nine opponents below that threshold.

30. Josh Allen > Josh Allen. What a day for the Jacksonville linebacker, who had his second three-sack game of the season and became the first player with such a trifecta at Wembley.

31. Or Josh Allen < Josh Allen. What a day for the Buffalo quarterback, who posted a perfect passer rating (158.3) in a game for the first time in his six-year career. He also had at least four TD passes for the 12th time (playoffs included) and generated five total for the fourth time.

32. Finally, ICYMI, if you thought merging the NFL and Nickelodeon’s slime was something, hopefully you caught snippets of the Jaguars-Falcons game played in the world of Pixar’s “Toy Story.” Can’t be long before Trevor Lawrence is getting Woody and Buzz out of trouble.

Follow USA TODAY Sports' Nate Davis on X, formerly Twitter @ByNateDavis.