Stemming across the defensive line is a simple yet effective tactic that new defensive coordinator Andy Avalos will implement in the Oregon Duck defense. In short, stemming is a shift from the defensive line, right before the snap of the ball, used to confuse the offensive line. The better the defense is at recognizing the offense’s snap count, the more effective the tactic is.
Defensive Line Technique Chart
Above is a defensive line technique chart that will be a useful reference as we move along. The numbers represent the position of a defensive lineman in relation to the nearest offensive lineman. For example, a 0 technique would be a defensive lineman aligned head up on the center, and a 1 technique would be shading the center to either side of the center.
Stemming actually has multiple benefits. The first of which is to disguise the front that the DL will be in at the snap. The OL will know its assignments based upon how the DL aligns, but those assignments can suddenly change a split second before the play begins when stemming occurs. This puts an immense amount of stress on the OL to adjust on the fly. The moving diagram above illustrates one of Coach Avalos’ most used DL stemming techniques.
Notice how the Stud defensive end is not a part of the shift; he rarely is. In the video above, Boise State aligns in a more traditional front before stemming to more of a Bear look. You can get a real good look at the shift above. The DE stems from a 5 tech to a 4i, the NT from a 2i to a 0, and the DT from a 3 to a 4i. The stem is initiated by a motion call from one of the interior linebackers.
The Ducks will also implement stemming in their third down passing defense. Again, neither stud takes part in the shift, only the two true DL. In the above moving diagram-the nose tackle stems from a 2i to a 0 tech and the defensive tackle stems from a 3 tech to a 5 tech.
I like how this shift could put a significant amount of pressure on the right side of the OL. On top of the stem, the defense is blitzing from the left and the Stud on the right stunts around the defensive tackle to his side. The quick throw by Justin Herbert is probably the only thing that kept him off of the ground on this play.
Another benefit of stemming is that the shift could cause the OL to commit a false start penalty. That’s easy yardage for the defense. I believe this is going to be a really advantageous tactic for the Ducks, and the fact that Coach Joe Salave’a has extensive experience with it from his time at Washington State makes it that much more exciting.
Coach Eric Boles
Newark, Ohio Top Photo Credit: Kevin Cline
Spencer Thomas, the FishDuck.com Volunteer Editor for this article, is an attorney for the Social Security Administration in Atlanta, Georgia, and coaches High School Football for Hillgrove HS in Powder Springs, GA.
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Eric resides in Central Ohio, just outside the capital city of Columbus. He is a former offensive assistant and return game coordinator for the Ohio State – Newark/Central Ohio Technical College Titans football program.
He is an OSU-N graduate, having completed a Bachelor of Arts program in psychology.