There are positions on a football field where you want to be truly great if you want to rise above other teams. Quarterback is at the top of that list for obvious reasons.

There are other positions — or perhaps position groups — where being merely adequate will suffice. I might argue offensive line is at the top of that list. A functional offensive line, one that more often than not holds up in key moments, is enough for a championship-caliber team to function. A detriment of a far below-average line exceeds the benefit of a dominant one, but it better at least be decent.

Those two notions go hand in hand when talking about the Vikings. They have invested heavily at quarterback, first giving Kirk Cousins a fully guaranteed three-year, $84 million contract and then adding a two-year, $66 million extension to that deal that essentially kicks in during the 2021 season.

We can argue about where Cousins falls on the average-good-great spectrum, but what isn't in doubt for pretty much any quarterback is this: They will tend to fare better when they aren't under pressure, and a good bit of that is attributed to the play of the big guys in front of them on the offensive line.

With the Vikings, though, there is a second push-pull dynamic: the salary they pay Cousins — only six other quarterbacks make more in 2021 than the $33 million average the Vikings now pay him — can lead to difficult roster decisions elsewhere. That is particularly true in 2021, with a salary cap reduced to $182.5 million as a result of the pandemic.

That came to a head this week when the Vikings faced a tough decision on offensive tackle Riley Reiff. He started all but six games in the last four seasons at left tackle and generally did a credible job. In 2020, he probably had his best season here: just one sack, 13 hurries and 21 pressures allowed in 15 games — all his best numbers with the Vikings.

A line full of players of Reiff's caliber would be considered adequate. The Vikings' line, however, has generally featured 2-3 players at that level and 2-3 players below that level.

Reiff was expensive, and as a result was cut — saving the Vikings $11-plus million on next year's cap. It's something I talked about at the outset of Thursday's Daily Delivery podcast.

Unless the Vikings can smoothly transition 2020 second-round pick Ezra Cleveland into a starting tackle role and/or sign other lower-cost reinforcements around him, they face the likelihood that their offensive line in 2021 will be below-average, as it has been as a whole in many recent seasons.

And that will increase the likelihood that when they need Cousins the most — late, in the clutch — he will be under duress and unable to deliver.

Time will tell how much they miss Reiff, but for now he seems like a paradox: A player they couldn't afford to keep, but one perhaps more that they couldn't afford to lose.