GREEN BAY – For a prime case study in how momentum can impact an NFL season, yet how quickly it can change, look no further than the Minnesota Vikings and Green Bay Packers in 2016.

In mid-October, the Vikings were enjoying their bye week at 5-0. Their new quarterback, Sam Bradford, had taken the reins with authority and Mike Zimmer’s defense was stifling every opponent in sight.

Through five games, no one except Green Bay in Week 2 had come within nine points of Minnesota, and the Vikings were the prohibitive favorite to win a second straight NFC North title.

Then it all changed.

Not only did the Vikings come out of their bye week with a four-game losing streak, but their rough stretch has now encompassed seven losses over nine games. With two weeks left, Minnesota cannot win the division.

The two wins over the last nine could have been many more. The two losses before the first victory were both by six points, including one in overtime. The two losses before the second were by a combined five points.

Another winning streak easily could have been fashioned somewhere in there, but it didn’t happen, and now Minnesota’s wild-card hopes are hanging by a thread as they come into Lambeau Field on Christmas Eve.

The Packers have ridden a similar roller coaster but with different timing.

At 4-2 on Halloween weekend, Green Bay lost in the final moments at Atlanta, and suddenly that mushroomed into a four-game losing streak.

Then quarterback Aaron Rodgers professed the utmost confidence in his team by declaring it can “run the table,” and a Monday night road win at Philadelphia began what is now a four-game winning streak with two more wins needed to take the NFC North.

“It was one of those deals where we knew once we got that first win we could get rolling,” receiver Randall Cobb said this week. “It was a matter of getting that first one, and once we got it, things have kind of fallen into place. We’ve gotten some guys back healthy, and we’ve gotten a lot of guys making key contributions to our team.”

The turnaround also has manifested itself in the key area of turnovers. Through 12 games this season, the Packers were an unsightly minus-5 in turnover differential, a statistic that stuck in Head Coach Mike McCarthy’s craw.

Two weeks later, after 10 takeaways and no giveaways against the Seahawks and Bears, the Packers have jumped from the bottom quarter of the league to the top quarter at plus-five. Go figure.

What does all this mean for Saturday afternoon? In the end, not much.

The Vikings are coming off their worst loss of the season, 34-6 at home to Indianapolis, but they’re just as likely to play with their hair on fire against the Packers as they are to continue fading into the sunset.

Meanwhile, the Packers were force-fed a lesson just last week as to how rapidly switches can be flipped in this league.

Heading into the fourth quarter in Chicago last Sunday, Green Bay had outscored its last two opponents 65-20. But a defense that had allowed just 46 points and taken the ball away a dozen times over the previous 3¾ games suddenly couldn’t get off the field.

“We’re sitting there, four straight series with a takeaway, and all of a sudden we can’t get any pressure on the quarterback, we can’t get tight coverage, and they get the momentum going,” defensive coordinator Dom Capers said of the Bears, who scored two straight touchdowns and came a few yards from a third late in the fourth quarter.

“That’s the way this game is in the NFL. You can’t ever relax. You can’t ever think you have control of the game because it can change on you in a flat second.”

For all the positive mojo they have going over the past month, the Packers appear to be taking the ephemeral nature of momentum to heart with the division-rival Vikings and Lions standing between them and a division title.

Asked this week if it means something that the Packers have turned their season around, Rodgers was rather blunt.

“Not if you don’t finish it off,” he said. “Like I said after the (Chicago) game, you know what it feels like to be 4-6. It’s a tough situation to be in. It’s frustrating. It’s a struggle, it’s a grind.

“But luckily in those situations we stuck together and didn’t have any fracturing in the locker room. No finger-pointing, no unnamed sources coming out taking shots at guys. We stuck together, and we all believed.”

The Packers believe momentum is on their side, but they also know it can only take them so far.

“It’s only big if you continue to work and take care of business,” receiver Jordy Nelson said. “It can be shut off immediately. That’s how quick it can be gone.

“That’s the situation we’ve put ourselves in, to make sure we’re playing our ball, all game long, all four quarters. Especially in these division games, they can be taken from you in a heartbeat. We just have to continue to play well, prepare well, execute and finish.”