Can anyone stop Tom Brady and the Patriots the way the Broncos did in last season’s AFC title game? (Christian Petersen/Getty Images)

The New England Patriots are widely acknowledged to be the NFL’s best team at the moment. To some observers, they have lapped the rest of the NFL field, going 3-1 while quarterback Tom Brady served his Deflategate suspension and 4-0 since Brady’s return. Is a fifth Super Bowl title for Brady and Coach Bill Belichick inevitable?

Maybe so, maybe not. Last season, remember, the Patriots looked unbeatable for much of the regular season, winning their first 10 games. But they were undone by injuries to key members of Brady’s supporting cast on offense and a leaky offensive line. A 2-4 stretch to close the regular season cost them the top seed in the AFC playoffs. They had to go to Denver for the AFC title game and they couldn’t block Broncos pass rusher extraordinaire Von Miller, suffering a bitterly disappointing defeat one step shy of the Super Bowl.

The offensive line has been better this season and Brady has been otherworldly since his return. He has a passer rating of 133.9 and has connected on 73.1 percent of his throws. His four-game pace would produce–over a full 16-game season–5,276 passing yards, 48 touchdown passes and no interceptions. He easily could be the league’s MVP while playing only 12 games.

The offense around Brady is talented and deep. Brady has two productive pass catchers at tight end in Rob Gronkowski and Martellus Bennett. He has an effective group of wide receivers in Julian Edelman, Chris Hogan and Danny Amendola. He has a running threat in tailback LeGarrette Blount.

There are some potential issues on defense. The Patriots rank second in the league in scoring defense. But they’re only 15th in total defense (based on yards allowed). They’re 15th against the run and 18th against the pass. So teams are finding ways to move the football against them reasonably well, but are not managing to turn their opportunities into enough points. The Patriots stunned much of the football world when they traded Pro Bowl linebacker Jamie Collins to the Cleveland Browns.

There are some significant regular season tests still to come, most notably this Sunday night at home against the Seattle Seahawks and Dec. 18 at Denver. There is little room for error, with the two-loss Oakland Raiders and Kansas City Chiefs challenging them for the No. 1 seed in the AFC playoffs.

Are the Patriots, with Brady playing at this level, unbeatable? That’s unlikely. Few teams looked more unbeatable than the 2007 Patriots, who won their first 18 games but then were upset by the New York Giants in the Super Bowl. But it’s a league of matchups, and it probably would take a team with favorable matchups and playing very well to get the job done against these Patriots.

“I think it comes down to how much you can bother Brady,” a front office executive with an AFC team said. “You need to be able to get some sacks. But it’s more than that. You need to be able to hit him a lot. You need to be able to make him move. You need to be able to disrupt him. That’s what you saw when the Giants beat them in those Super Bowls. That’s what you saw in the [AFC] championship game last year with the Broncos.”

A personnel executive with an NFC team said: “It’s pass rush. But I also think you need to have an offense that will put some points up against them. You have to be versatile against them in your offensive approach. If you’re a team that relies on one guy, that plays into their hands because that’s what they do so well. They take away your number one guy.”

Here’s a quick look at the teams that might have the best chance to halt the Patriots either in the AFC playoffs or in the Super Bowl:

Broncos: The defending Super Bowl champs are only the third-best team in the powerful AFC West at the moment, behind the Raiders and Chiefs. They are not as deep on defense as they were last season. But the pass rush remains formidable. Denver ranks second in the NFL with 28 sacks. The offense has been turned over to second-year quarterback Trevor Siemian. It might be difficult to envision a young quarterback beating Brady and the Patriots in a postseason game. But the Broncos didn’t win the Super Bowl last season because of their quarterback play; they won it because of their defense. The craftiness of defensive coordinator Wade Phillips should not be discounted, either.

Seahawks: They rank third in the league with 27 sacks. They also have standout players in the secondary capable of dealing with the talent of the Patriots’ receivers. Russell Wilson is a quarterback able to take over a game. But Seattle hasn’t been able to generate much of a running game minus the retired Marshawn Lynch. The meeting Sunday night will provide a glimpse of how the two teams match up. It also could be a positive Super Bowl precursor for the Seahawks. Both of the Giants’ Super Bowl triumphs over the Patriots came after the teams met during the regular season.

Cowboys: They have become a glamour team again with rookie Dak Prescott at quarterback, and what could be more intriguing than a Cowboys-Patriots Super Bowl? Prescott taking the starting job from an injured Tony Romo has been likened to Brady once taking the Patriots’ quarterback job from an injured Drew Bledsoe. Yes, Prescott has been remarkably poised for a young quarterback. But he’d still be a rookie trying to outshine Brady on the sport’s biggest stage. The Cowboys have a mediocre pass rush. But they would have the prospect of trying to control the game with their powerful offensive line and the running of rookie tailback Ezekiel Elliott.

Raiders: Quarterback Derek Carr has become an MVP candidate and the Raiders do have some variety on offense. They have two terrific wideouts in Amari Cooper and Michael Crabtree. They used their running game to win in Denver this past Sunday night. They have not been a good pass-rushing team so far this season. But they do have one dominant pass rusher in Khalil Mack, and there is the possibility that the NFL could reinstate Aldon Smith at some point.

Chiefs: They have won 17 of their last 20 games, including the playoffs. They just have gotten back their top defensive player with Justin Houston’s activation from the physically unable to perform list. But is the offense dynamic enough to beat the Patriots in a meaningful game?

Vikings: They have the defense. Their defensive line might give the Patriots fits. But the offensive line has fallen apart lately. It’s probably a moot point, since it has become increasingly difficult to envision the Vikings reaching the Super Bowl with their recent downward spiral.

Giants: They have no pass rush. But they still have Eli Manning at quarterback. He has been a Patriots’ nemesis in two Super Bowls. They have a wide receiver, in Odell Beckham Jr., who can be tough to contain even when that is the entire defensive focus. There would be no reason to believe the Giants could beat the Patriots in a Super Bowl matchup. But, then, there was little reason to believe the Giants would prevail the last two times they met the Patriots in Super Bowls.

Steelers: The Steelers are tied with the Giants for the fewest sacks in the league, with 11 each. They might not even be a playoff team, as they have stumbled to 4-4 after losing last Sunday in Baltimore. But maybe, just maybe they will put things together in the second half of the season. And if they do, they wouldn’t be an opponent that the Patriots or anyone else would look forward to facing in the postseason, given the capabilities of an offense led by quarterback Ben Roethlisberger, wide receiver Antonio Brown and tailback Le’Veon Bell.

Ravens: They never have been intimidated by the Patriots. The defense is good enough. But the Baltimore offense simply hasn’t been all that great, and quarterback Joe Flacco too rarely this season has resembled a former Super Bowl MVP.

Falcons: The pass rush is improved. Quarterback Matt Ryan has been superb, and the Falcons have managed to win some games when opposing defenses have held wide receiver Julio Jones relatively in check. But could they really rise to the Super Bowl occasion and give the Patriots a game? That seems like a stretch.