49ers: Chip Kelly, Constraint Theory and Packaged Plays

At a later date, we’ll cover all facets of the Chip Kelly spread offense for the San Francisco 49ers, but for now we’ll look at how Chip uses the running game to set up the passing game and vice versa.

At all levels of football, a good offense will simplify each aspect of its playbook for their players while also keeping defenses off balance. San Francisco 49ers head coach Chip Kelly’s offensive philosophy is simple: everything revolves around the inside-zone running play, the base play of his no-huddle spread offense.

Everything is designed to give the offense a number’s advantage by spreading opposing defenses out and forcing them to declare the intentions.

At a 2012 coaching clinic, Kelly asked:

The no-huddle not only defines his particular offense, but also defines how he runs his program, from Oregon, to Philadelphia, to San Francisco.

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Good defenses will spend all week scheming to take away what a team does best – their base set of plays – and will have thought of every possible way to adjust to them.

Enter the constraint play.

Constraint plays work by punishing the defense where they are the weakest, i.e., where they are not bulked-up to stop one facet of the pass or run. Constraint plays exploit these areas. It could be a six-man box while taking the pass away or it could be cheating defenders trying to play the run.

Typical constraint plays include the draw to punish defenders who quickly get up-field on a pass plays, bubble screens that punish defenders sneaking into the box, quick slants or hot routes that punish blitzing defenders. Constraint plays punish defenders for getting out of position and force them to get back to their base defense so an offense can do what it does best.

One way Kelly uses constraint play in his offense is through the use of packaged plays. In Kelly’s offense, the packaged play combines his base run with quick passes in the same play. These packaged plays, or run-pass options (RPOs), allow the quarterback — and really, the defense — to determine the best option after the snap based on the action of a key defender or two.

On any given play, the quarterback could have as many as three or four options (handing the ball off, keeping the ball on a zone read, throwing a screen, or throwing a pass down field) and must determine his best option.

In Kelly’s offense, this is done by determining where the offense has the numerical advantage as determined by his pre-snap read and the post-snap movement of the defense.

(GIF: NFL GameRewind)

In Kelly’s offense, the most basic version of the run-pass option involves a simple bubble screen on the backside of his base run, the inside zone.

(GIFs and Image: NFL GameRewind0

In the above cut-up and gif, you can see the basic play design of the Eagles run-pass option with the inside zone or the quick screen under Kelly.

The play below shows a similarly designed play by former offensive coordinator Geep Chryst that nets wide receiver Bruce Ellington 30 yards after the catch. You can also see quarterback Colin Kaepernick look for the outside-zone run first. Kaepernick pulls the ball out when the defensive end crashes the running lane and he fires a quick pass to Ellington on the left side.

(GIF: NFL GamePass)

For the bulk of the offensive players, the play is no different than the base inside-zone run. Whether the quarterback throws the screen or hands the ball off, the offensive line and the receivers still block downfield as if it were a run.

Eagles center Jason Kelce in Philly Mag said of the offensive line’s responsibilities.

As the quarterback comes to the line, he’ll be checking the defensive alignment outside the box to see if there is any kind of numerical advantage. Adding a bubble screen to the backside of the base run play gives the offense a built-in option to take advantage of a defense that overloads the box to play the run.

If everyone is accounted for outside the box, he simply hands the ball off, but if the defense is out-manned to a particular receiver side, the quarterback will quickly take the snap and fire off the bubble screen. The decision to run or pass is based on a key defender, usually an alley defender like a corner, safety or outside linebacker. The key is to make that defender guess run or pass and simply get the ball to where he isn’t.

As Kelly’s tenure progressed with the Eagles, he added in new wrinkles that still incorporated the inside zone but also ones that sought to take advantage of the perimeter players (safeties, corners).

Facing a 4th-and-12 with two minutes left, up 34-20 against the Lions, Kelly put the decision in his quarterback’s hands. The wrinkle here, instead of the wide receiver bubble screen as option No. 2, was a tight end delayed release.

(Image: NFL GamePass)

The play, like so many others in Kelly’s playbook, gives the quarterback options. On this particular play, quarterback Nick Foles reads Lions safety (No. 27) Glover Quin. If Quin cheats toward the line, Foles knows tight end Brent Celek will be wide open. If Quin drops into coverage, Foles would hand the ball of to the running back.

(Image: NFL GamePass)

The play works to perfection. The Lions defense reads run all the way thanks to the zone blocking movement by the Eagles offensive line. Quin crashes the line and Celek releases as Foles pulls the ball out and floats one for a 27-yard gain to seal the win.

(GIF: NFL GamePass)

The last variant we’ll look at is the inside zone with four verticals concept.

(Image: NFL GamePass)

The pre-snap look on a 3rd and 9 against the Giants shows man coverage underneath a single high safety (cover 1). The Eagles line up in a two-by-two formation with four wide receivers.

(GIF: NFL GamePass)

The cut-up above shows LeSean McCoy getting the handoff but notice what the receivers are doing: running their routes vice blocking. The concept is called “four verticals” and “it is designed exactly the way you’d expect: four receivers run straight (more or less) down the field, dividing the field into segments,” wrote Chris Brown back in 2009.

(Image: NFL GamePass)

There are many variations to four verticals (read the Smart Football post here). Generally the receivers all run go-routes or some kind of deep vertical post or angle route. The common theme among the variations is that receivers have to make decisions based on how the defense is playing. But the basic idea is to set up one-on-one matchups and create conflict for the one safety who has to decide what to do on four vertical routes.

(Image: NFL GamePass)

The pre-snap look shows a six-man box against the Eagles five offensive lineman. That means quarterback Michael Vick has to read the second option in his progression: Jason Pierre-Paul. That added element is the more famous “read option” where Vick has the ability to pull the ball and run depending on how the defensive lineman plays the line.

(Image: NFL GamePass)

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No matter what Vick decides, he has to decide quick between handing the ball off, running, or throwing one of the vertical routes or the offense risks an illegal man downfield penalty due to the zone blocking assignments. On this particular play, Pierre-Paul stays at home, so Vick hands the ball off. McCoy spots a crease in between Jason Kelce and Todd Herremans.

(GIF: NFL GamePass)

The 49ers offensive personnel are natural fits for these plays. By spreading the field, Kelly is forcing the defense to remove players from the box and by putting the quarterback in the shotgun, he’s taking away the defense numerical advantage by making the quarterback an extension of the blocking scheme in a zone read.

Everything he does will theoretically put the defense in a position to get back to their base defense and where Kelly can get the offense back to doing what it does best: running the football.

Next: 4 Players Who Could Struggle Under Chip Kelly

All statistics, records and accolades courtesy of Pro Football Reference unless otherwise indicated.

49ers: Chip Kelly, The Constraint Theory Of Offense, And Packaged Plays

By Rich Madrid | Jul 11, 2016

At a later date, we’ll cover all facets of the Chip Kelly spread offense for the San Francisco 49ers, but for now we’ll look at how Chip uses the running game to set up the passing game and vice versa.

More from Niner Noise

More from Niner Noise