Chip Kelly offense 101: Passing game, part 4

Stretching defenses both horizontally and vertically in the passing game is an idea that dates back over a half-century to Sid Gillman, the Hall of Fame coach of the Los Angeles Rams (1955–59) and San Diego Chargers (1960–71), and father of the modern passing game. Though they might have been repackaged a bit, Gillman’s innovations can still be seen every fall Sunday.

Bill Walsh was among the first to realize you could combine Gillman’s horizontal and vertical stretches into a single pass play, commonly referred to as a triangle stretch. In the final part of our Chip Kelly passing game breakdown, we’ll be looking at how the 49ers’ new head coach implements a pair of passing concepts pioneered by a former 49ers head coach over 30 years ago.

(Note: If you’ve missed any of the first three parts in this series, you’ll want to give them a read here, here, and here, as today’s post builds upon the information covered in the previous articles.)

Snag

By combining a horizontal and vertical stretch into the same concept, triangle stretches theoretically give the quarterback an option against any coverage type. Pure horizontal or vertical stretches are still more effective if you’re able to properly identify the coverage prior to the snap — e.g., all curl will always have an open receiver against your basic Cover 3 defense. As you can imagine, however, accurately diagnosing the exact coverage pre-snap isn’t an easy task, which is where the versatility of the triangle stretch comes into play.

No play is more synonymous with the triangle stretch than the snag concept.

Snag is a three-man route combination featuring a corner route, a flat route, and a snag route. Against two-deep zone coverage, the quarterback has a vertical stretch on the cornerback with the corner and flat routes; against three-deep zone coverage, there’s a horizontal stretch on the flat defender with the snag and flat routes. Once the quarterback identifies the coverage type, he simply keys the appropriate defender — either the cornerback or flat defender — and makes the throw based on that defender’s action.

When dealing with man coverage, the quarterback’s approach changes. "It starts off initially, you don’t know if it’s zone or man, but really if it is man then what we’re looking for is the best matchup," Kelly explains on PhiladelphiaEagles.com.

Much like we discussed with the smash concept against man coverage, in most cases this will come down to corner route or the backside receiver, depending on where the free safety opts to help.

Stick

The similarities between the snag and stick concepts are numerous. They’re both three-man route combinations comprised of a two-man horizontal and two-man vertical stretch. Those combinations attack roughly the same areas of the field, and affect the defense in the same way. Only the specific routes, and timing of those routes, change.

Stick is a quicker developing concept than snag is, with three-step timing for the quarterback as opposed to five-step. And here, the stick-flat combo provides the horizontal stretch, and the fade-flat pairing stretches vertically.

Considering the name of the play, it won’t surprise you to learn the stick route is where the ball ends up most of the time. How the finer points of the stick route are coached will vary slightly from team to team, but in most cases it functions like short out route. The receiver runs vertically to a depth of about six yards and turns outside, settling in the void against zone and separating to the sideline against man.

One of the things defenses can do to combat these triangle stretches is to rotate the underneath coverage, giving them an additional defender to the triangle side of the field. With every tactic there are downsides, however, and this rotation leaves the defense light on the backside. Knowing this, most offenses will pair stick with a separate concept to the other side of the field, such as double slants, to exploit the additional space on the backside. And as we’ll learn in the next article, the final part of our Chip Kelly 101 series, Kelly routinely pairs the stick concept with one of his base run plays, further conflicting the defense.