The Minnesota Vikings defensive line must face a familiar foe on Sunday in the Green Bay Packers offensive line. A unit that has established and developed a unique technique of “legal holding” that utilizes NFL rules and referee tendencies.

The Minnesota Vikings always have their hands full when it comes to the playing the Green Bay Packers, usually in regard to the extraordinary and eccentric talents of Packers quarterback Aaron Rodgers.

But as talented as Rodgers is–physically and by improvisation–he has an advantage that few fans realize, an offensive line that has been schooled in the art of modern trench tactics by Packer offensive line coach James Campen, now in his 20th season with the team.

Q: What is Campen’s tactic?

Campen’s technique goes by a few terms. One is the “hands outside” stance and another, more appropriately, is called the “hug” technique.

Most defensive linemen, most notably, defensive ends have a varied selection of ways to initiate contact with offensive tackles. They can punch, swim, spin, or even “dip and rip” upon first contact, attempting to take the lineman out of his position defending the offensive backfield or quarterback pocket.

What the Packers have developed, is a solid–but not perfect–way to neutralize these techniques, as well as the speed and athleticism of most NFL defensive ends.

Contrary to common perceptions, NFL rules do allow for offensive linemen to do some grabbing and holding, as long as they keep their arms inside and between the armpits of their engaged opponent.

The Packers have used to this rule, bent it, and often gotten away with many bald-faced illegal holds away from the eye of the referees.

This is how it usually happens:

1. The Green Bay offensive lineman takes on the rush and waits for the defensive player (usually an opposing lineman) to make contact, giving him the first move.

2. The Packers blocker then “hugs” the defender, getting his hands outside that initial contact or move.

3.Then, the Green Bay offensive lineman squeezes in his open arms grasp, holding the defender’s arms inside his “hug” and often getting away with a grab or hold of his opponent’s shoulder pads and sleeves.

Because first contact is the most important moment of a pass rush, it is where the Packers’ offensive line makes its hay, giving Aaron Rodgers time to choose a passing option or run the field around, by, or away from the engaged defender.

Head coach Mike Zimmer is brainy guy. He’s also a coach that learns from losing football battles.