The Rams are 3-0 but face a tough upcoming schedule. (Harry How/Getty Images)

The third week of the NFL season didn’t just defy the odds — it was flat-out weird. Despite being 17-point underdogs, the visiting Buffalo Bills blew out the Minnesota Vikings, 27-6, after being the worst team in the league for the first two weeks. The Detroit Lions, who had struggled to an 0-2 start, dominated the New England Patriots, 26-10. In total, the underdog won six of Sunday’s 14 games.

It was crazy. And it also revealed an important lesson: There are no great teams this season — at least not yet.

The most likely exceptions to this rule are the Kansas City Chiefs and Los Angeles Rams, both of which improved to 3-0 with impressive wins Sunday. But don’t lull yourself into thinking both teams are automatically heading to 13- or 14-win seasons. Just look at their schedules. The Rams face the Vikings on Thursday, and they might be without their two best cornerbacks, Marcus Peters and Aqib Talib; both suffered ankle injuries in Sunday’s win over the Chargers. After that, they draw a dreaded three-week road schedule — at Seattle, at Denver, at San Francisco. That’s followed by a home game against Green Bay and a trip to New Orleans.

The Chiefs face similar problems. They play at Denver next Monday night, host Jacksonville, play at New England and then host Cincinnati and Denver.

“It’s tough in the National Football League to win games,” Chiefs Coach Andy Reid said after his team’s 38-27 win over San Francisco.

It’s particularly tough in the season’s first month. A week ago, the Packers-Vikings tie defined the league. It had roughing-the-passer controversy, high-powered offense, missed field goals, overtime problems and more. On Sunday, those two played like teams with empty gas tanks. The Packers allowed the Redskins to score the game’s first 14 points, and the Bills jumped to a 27-0 lead before halftime.

“It was probably as poor of a first half as I’ve seen in quite a while,” Vikings Coach Mike Zimmer said. “We didn’t get anything done offensively. Special teams, we made a lot of mistakes. Defensively, we allowed the quarterback to get out and scramble, and we turned a couple guys loose in coverage again today.”

As bad as it was for the Vikings, it might have been worse for the Packers in their 31-17 loss to the Redskins. Aaron Rodgers complicated his knee injury by adding a hamstring injury to it, and this quote from Coach Mike McCarthy is scary.

“He’s going to be dealing with this for a while,” McCarthy said of Rodgers. “He gutted it out and moved out of the pocket, more than I like, but I mean he’s . . . I really don’t know the extent probably until Monday.”

Rodgers will gut things out and find a way to stay on the field, but he’s going to struggle if he doesn’t get support from the running game, and the offensive line is now banged up, too, with right tackle Bryan Bulaga suffering a back injury and right guard Justin McCray hurting his shoulder. And now both Minnesota and Green Bay trail the Chicago Bears, at 2-1 the leaders of the NFC North.

Another NFC contender with reason for worry? The Atlanta Falcons, who have lost defensive starters Keanu Neal, Ricardo Allen and Deion Jones for the season with injuries, and let Drew Brees throw for 396 yards in the Saints’ overtime victory. They are 1-2 and in last place in the NFC South, which looks to have two strong teams in the Saints and Panthers, and maybe a third in the surprising Tampa Bay Buccaneers.

The AFC contenders have their fair share of issues as well, starting with the Patriots. They were hopeless in their loss to the Lions. Trade pickup Josh Gordon was inactive with his hamstring injury. Julian Edelman has one more game to serve on his suspension. Tom Brady completed 14 of 26 passes for 133 yards and had only four completions for 43 yards to wide receivers.

Even worse, the Patriots looked like a team that lacked playmakers on defense. Matthew Stafford threw for 262 yards, and a Lions offense that struggled to run the football had 159 yards on the ground.

“We didn’t do a good enough job in any area,” Coach Bill Belichick said.

If the Patriots lose to the Dolphins next week, they would be three games behind them in the AFC East. That’s remarkable, given that Miami was projected to be a six- or seven-win team.

The Jaguars put themselves atop the AFC with last week’s home win over the Patriots, then turned around and lost a home game, 9-6, to a Titans team that started Blaine Gabbert at quarterback and went to a banged-up Marcus Mariota after Gabbert was knocked out of the game. The loss pointed to Blake Bortles and the offense.

“I think, especially the way our defense is and the way they play, we have to score one touchdown and win the game,” said Bortles, who threw for just 155 yards and was sacked three times. “To score six points in four quarters, that’s bad as an offense.”

Leaguewide this year, the NFL stands for No Firm Leader.

Quick hits from around the NFL:

The NFL’s effort to add protection for quarterbacks continues to draw criticism. There were nine personal foul calls for roughing the quarterback, bringing the season total to 30. And once again, Clay Matthews of the Packers was the headliner. Last week, his penalty for a hit on Kirk Cousins wiped out an interception that would have clinched a victory over the Vikings.

In Sunday’s loss to the Redskins, Matthews was flagged for another questionable hit. Before the season, Matthews had only four roughing-the-passing penalties during his career. He has three in the past two weeks.

“Unfortunately, this league is going in a direction I think a lot of people don’t like,’’ Matthews said. “I think they’re getting soft. The only thing hard about this league is the fines that they levy down on guys like me that play the game hard.”

The Earl Thomas story keeps getting weirder. Thomas executed what is being called a “hold-in” by skipping two Seahawks practices last week. He wants a contract extension or a trade to a team like the Dallas Cowboys. On Sunday, Thomas had two interceptions and played an exceptional game in a 24-13 victory over the Cowboys.

After the second interception, he turned to the Cowboys' sideline and bowed, which resulted in a 15-yard penalty for taunting. The interception all but sealed the Seahawks' first win.

According to people with knowledge of the trade discussions, at one point the Cowboys might have been willing to give the Seahawks a second-round draft pick for Thomas, but the Seahawks want more.

Thomas’s play has been sensational, but he clearly is going to do things his way if he doesn’t get a contract extension.

“I need to make sure my body is 100 percent,” Thomas said of his willingness to miss practice. “I’m investing in myself. If they are investing in me, I would be out there practicing. But I feel like, if anything, I don’t give a damn if it’s small. I got a headache, I’m not practicing.”

Before the game, security guards at CenturyLink Field were told to let Thomas’s wife come to the Cowboys’ sideline. Now that the Dallas game is behind them, the Seahawks will have to determine whether the Thomas distraction is too much.

The Jimmy Garoppolo injury is a game-changer for the 49ers. If they felt like they were a playoff team, they might have considered a trade for Le’Veon Bell to boost the running attack following Jerick McKinnon’s season-ending injury. Instead, this is probably another rebuilding year for the team, which will start C.J. Beathard if Garoppolo is done for the year.

“Anytime you lose your starting quarterback, that is a big deal,” 49ers Coach Kyle Shanahan said. “So obviously I feel for him personally. I know how disappointed he is.”

Week 3 was a good one for the league’s young quarterbacks. Josh Allen of the Bills beat the Vikings. Baker Mayfield came off the bench Thursday to beat the Jets and was named the Browns’ starter Monday. Josh Rosen, who was put in during the final minutes of Arizona’s loss to Chicago, is closer to a starting job, given the Cardinals’ 0-3 start and poor production under Sam Bradford.

And Kansas City’s Patrick Mahomes remains one of the best stories in the NFL. He threw three touchdown passes in the Chiefs’ win over the 49ers and now has 13 in the first three weeks, breaking Peyton Manning’s record of 12.