Some of us like to think of sports rivalries as always-on, volume-cranked-to-11 affairs.
That's true to an extent, but it's also true that if you really think about it there are some peaks and valleys along the way. Not every year in a football rivalry, for instance, is equally meaningful or intense.
The Vikings vs. Packers rivalry in the last 20 years or so has followed an undulating, sine wave motion. There is always a certain baseline intensity experienced by the players and particularly the fan bases, but not all years are the same. Some, in fact, are duds.
What is also true and fun about the rivalry, though, is that whenever it starts to drift into one of those valleys, something seems to happen to jolt it back to the top.
The rivalry didn't start, obviously, with the drafting of Randy Moss in 1998 by the Vikings, but let's start there to illustrate the point.
In the two seasons before the Vikings drafted Moss, the Packers went to the Super Bowl twice with Brett Favre — winning one and losing one. Moss changed the dynamic with an electric performance at Lambeau Field in 1998, shifting the balance of power and leading to a string of memorable games over the next few years.
From there, it was still good for a few years but dipped a little from the peak of those early Moss years — only to shoot up again in 2004. The Packers scored two dramatic wins over the Vikings in the regular season, only to watch Minnesota come into Lambeau Field to win the first playoff game ever between the teams (capped by the Moss fake moon TD celebration).
Then there was another dip in the late 2000s until Brett Favre gave the rivalry the biggest jolt it has ever felt by coming to the Vikings for two seasons — the first a wild success for Minnesota, the second a revenge year for Green Bay.
Then 2011 was a 3-13 mess for the Vikings and the rivalry was diminished. But in 2012 the Vikings beat the Packers in the final regular-season game, only to lose at Lambeau Field in the playoff rematch. Then a dip. Then the memorable 2015 regular-season finale at Lambeau.
Now here we are in 2017, a year where I didn't really think the rivalry would have much fuel. The Vikings came into Sunday's game at U.S. Bank Stadium with all sorts of injuries — to their top QB, top running back and top receiver. The Packers were playing at a Super Bowl level and could have taken control of the division with a win.
Instead, of course, Anthony Barr knocked Aaron Rodgers out for the game and potentially the season with a collarbone-breaking hit. The Vikings won handily; in the aftermath Monday, you had two head coaches with wildly divergent opinions about what happened on the play.
Packers coach Mike McCarthy said Barr's hit (which was legal, by the way) was "totally unnecessary."
Vikings coach Mike Zimmer said this: "I don't know what the scrutiny is. We're playing football."
Vikings fans and Packers fans likely will pick sides in regard to how they view the hit, but they could probably agree on this: With both teams now at 4-2 atop the NFC North, and with a Viking having knocked out the Packers' future Hall of Fame quarterback, the rivalry is riding high once again.