Week 1 of the NFL season is in the books. We already have two leaders in the division and two teams playing catch up. It's still early, but here's a look at some developing headlines surrounding the four teams in the NFC North:

MINNESOTA

Record: 1-0

Week 1: Win over San Francisco, 24-16

Emerging headline: Can Vikings d-line be even better than last year?

Even head coach Mike Zimmer seemed impressed by the performance of those guys up front and with the debut of Sheldon Richardson joining the group.

In all, the Vikings' defensive line of Richardson, Linval Joseph, Everson Griffen and Danielle Hunter combined for eight of the nine hits on 49ers quarterback Jimmy Garoppolo and seven of the Vikings' nine run stops (gains of 2 yards or less), via the Minneapolis Star Tribune.

Richardson had three run stops, three quarterback hits and had a sack.

Twentyman: Now, to be fair, the 49ers did suffer a couple of injuries upfront along their offensive line and were forced to shuffle players around, but that Vikings group upfront was dominant. They were a big reason the 49ers managed just 16 points and suffered their first loss since Garoppolo was named the starter. Garoppolo threw three picks in the game, two coming on pressured throws.

Hunter had eight pressures and a sack. Griffen had four pressures and a sack.

This unit was dominant before the addition of Richardson. If last Sunday is any indication, offensive lines are going to have their hands full with the Vikings, if those guys stay healthy.

Quotable: "Now it's on tape, and I know what he's going to look like and what he's supposed to look like," Zimmer told the Tribune this week of Richardson. "He played real hard, pushed the pocket. There were two times that he took the guy with one hand and knocked him back. He played really, really well. We need him to continue to play like that."

Next up: at Green Bay (1-0), Sunday, 1 p.m.

GREEN BAY

Record: 1-0

Week 1: Win over Chicago, 24-23

Emerging headline: Will QB Aaron Rodgers be on the field Sunday vs. Minnesota?

It's just four days until the first showdown of the 2018 season between the Packers and Vikings, two teams expected to compete for the division title. Rodgers injured his knee in the first half of last week's game in Chicago. He left the game, but emerged out of the locker room after the half and threw three touchdowns to help the Packers come back and win.

Rodgers did not take part in Wednesday's practice.

Twentyman: There is no player in the NFL right now who is more important to his team than Rodgers. They are a completely different team when he's not in the game. We saw it last year and we saw it in the first half against the Bears.

The Packers have to think long term, but Sunday is a big one and decides who the top dog in the NFC North is after two weeks.

Quotable: "We're taking it one day at a time," Rodgers said Tuesday on The Dan Le Batard Show. "One day at a time."

Next up: vs. Minnesota (1-0), Sunday, 1 p.m.

DETROIT

Record: 0-1

Week 1: Lost to New York Jets, 48-17

Emerging headline: Was the dud on opening night a sign of things to come?

Lions fans are certainly hoping that isn't the case. The way the team has played throughout the preseason and to open the regular season doesn't exactly instill a lot of confidence, however.

The Lions lost in all three phases Monday night, and that has to be disappointing to head coach Matt Patricia and Co.

Twentyman: While Monday's game was hard to watch, the reality of Detroit's situation is that they are 0-1 alongside 15 other teams in the NFL with 15 more games to go. The great thing about the NFL is that there isn't much time to dwell on what happened the week prior, good or bad.

The Lions have an opportunity to go into San Francisco and play much better to earn a tough victory on the road. In order to do that, they know they have a play a lot better than they did earlier this week.

If they do go into San Francisco and find a way to win, the narrative changes, and the Week 3 matchup with the Patriots on Sunday Night Football gets all its hype back.

Quotable: "The good thing about this game is one of the things we try to do is build a lot of mental toughness and I think that's part of the game and that's something that we're all about," Patricia said. "So, for us it's real important to get the things that were wrong fixed as soon as possible. And try to get those mistakes cleaned up so they don't happen again, and then push forward and get ready to go play another really good opponent."

Next up: at San Francisco (0-1), Sunday, 4:05 p.m.

CHICAGO

Record: 0-1

Week 1: Lost to Green bay, 24-23

Emerging headline: Khalil Mack could speed up Chicago's rebuild.

Mack was a one-man wrecking crew for the Bears in that narrow loss to the Packers in Green Bay last Sunday night.

Mack became the first player in two years to have a sack, forced fumble, fumble recovery, interception and defensive touchdown in the same game. The last one to do it was Mack, according to the Chicago Sun-Times.

After being acquired just that week via trade a with the Raiders, and only getting limited practice time in Chicago's scheme, Mack played 42 of the Bears' 60 defensive snaps.

What happens when he's playing even more to all of the snaps and has a better grasp of Vic Fangio's scheme?

Twentyman: The interceptions, forced fumble, fumble recovery and sack were all impressive, but the most impressive play on the night for me was him almost chasing down Packers wide receiver Randall Cobb all the way down the field on Cobb's late 75-yard touchdown grab.

It was reminiscent of a play Ziggy Ansah made a few years ago when he tackled Adrian Peterson 70 yards down the field to save a touchdown and force a field goal. That was the year Ansah recorded 14.5 sacks and made the Pro Bowl.

Mack is immensely talented, but he's also 100 percent hustle, which is a lethal combination.

Quotable: "In the first half, Mack was pretty much what we thought, but we didn't know it for sure," Bears head coach Matt Nagy told ESPN Chicago this week. "Like I told you, we didn't know how many reps he would get or where he was at conditioning-wise. He was doing well, feeling well and making big-time plays."

Next up: vs. Seattle (0-1), Monday, 8:15 p.m.