Chip Kelly offense 101: Run game variants

The key to any good offense is possessing answers for all of the various problems defenses can present. It’s important to have a set of base plays that your offense is well versed in and comfortable running in any situation — in Chip Kelly’s run game that would be the inside zone, power, outside zone, and sweep.

Good defenses, however, will scheme to take away those base plays. They want to force you away from your bread-and-butter and out of your comfort zone, where they now possess the upper hand. When that inevitably happens, the offense must have some tendency breakers — adjustments to those base plays — in their back pocket to keep the defense off balance. Here are seven adjustments that Kelly loves to use with his base run game:

(Note: Because this article focuses on the adjustments, I won’t be rehashing many of the details for how Kelly’s base runs work here. If you missed those articles, or just need to brush up as you’re going along, make sure to check them out first here and here.)

Split Zone

Kelly’s primary method of controlling an extra defender in the box is with the zone read — the quarterback becomes an extension of the blocking scheme, tipping the numeric advantage in the box in favor of the offense, by "reading" the unblocked defender and making him wrong every time. All four of Kelly’s base runs can be modified to read a defender in this manner.

As a change-up, or when the quarterback lines up under center as opposed to the shotgun (a rare occurrence), Kelly will use the split zone to account for an additional box defender. The split zone, as the name implies, aims to "split" the defense in half to create a seam for the ballcarrier on the backside of the play. To accomplish this, offenses use a technique that Kelly calls the "sift" block. A blocker from the play side, typically a tight end in Kelly’s offense, comes across the formation to kick out the previously unblocked edge defender on the back side.

For the offensive line, regardless of whether the sift block is added to the inside zone or outside zone, absolutely nothing changes. They carry out the same assignments and use the same techniques as if a standard zone run had been called, which, as you’ll find, is a common thread among most of these adjustments.

Pin and Pull

Reach blocks can be some of most difficult blocks in football to execute. When "reaching," the offensive lineman is attempting to get to the outside shoulder of the defender and turn him back inside. Unless you have a superiorly talented lineman, attempting to reach a defender who is playing wide in his technique — e.g., asking a guard to reach a defensive tackle who is closer to the inside shoulder of the tackle than his own outside shoulder — is often a recipe for failure.

The "pin and pull" is an adjustment to the outside zone that converts a potentially-too-difficult reach block into a pair of much easier blocks for the offensive line to execute.

In a standard outside zone blocking scheme on the play above, the right guard would be responsible for reaching the defensive tackle lined up in his outside gap, while the right tackle would be responsible for getting up to the second level and blocking the outside linebacker. In both cases, the defense has the leverage.

With the pin and pull, the guard and tackle switch responsibilities, giving each of them easier blocks with more advantageous angles. The tackle pins the defensive lineman inside with a down block, and the guard pulls around him to kick out the linebacker.

Kelly loves to go to this adjustment against a "wide 3-technique" like we see in the example above (which, you could technically call a 4i-technique, but I think more people are familiar with the term 3-technique), in which the defensive lineman in the play-side B-gap is closer to the tackle than the guard.

Misdirection Sweep/Toss Sweep

When I looked at the outside run game, I didn’t show any examples of runs going to the same side as the running back’s initial alignment, but Kelly has a couple of ways to get this accomplished.

The first is by adding a misdirection element with the running back, which ends up looking like a more exaggerated version of the back’s path on Kelly’s power play.

The running back’s initial hop step away from the play side prevents him from hitting the hole too soon and helps sync up his timing with the pulling lineman leading the way.

Kelly will also toss the ball to his running back to get the sweep going to the same direction as the back’s alignment. Just as with the misdirection sweep above, there is a built-in delay element — by having the running back slow-roll into the play, having the quarterback take an extra step or two before tossing the ball, or both — so that the ballcarrier doesn’t outrun his blockers.

Nothing changes for the offensive line in either variant, though just as with the standard sweep play, Kelly will occasionally vary which two offensive lineman he pulls.

QB Sweep

Kelly only ran the quarterback sweep, at least with any sort of regularity based on my tape study, when Michael Vick was running the show in 2013. However, if Colin Kaepernick ends up sticking around and winning the starting job, it seems safe to assume we’ll see the play find its way back on to Kelly’s call sheet.

If you’re thinking — Damn, that looks familiar. Haven’t I seen the 49ers do this at some point recently? — you would be correct. Jim Harbaugh dialed up a similar sweep play, adding a crack-back block on the outside by a wide receiver and pulling both guards instead of the center/guard combo Kelly prefers, for Alex Smith on his famous touchdown run against the Saints in the 2011 playoffs. Kaepernick also ran a similar version to this play while Harbaugh was in town, with mixed success.

Midline Read

We’ve touched on the zone read a couple times now, and given how much attention it’s received in recent years, I’m sure most of you are comfortable with the basic mechanics of the play at this point. But a less-discussed variant of the zone read that Kelly’s offenses will deploy is the midline read, in which the quarterback reads an interior defender rather than the more typical read of the backside edge defender.

Reading an interior defender accomplishes a couple things for the offense beyond simply giving the defense another look to think about. NFL defenses have become more adept at defending the zone read and have added counters to their arsenal to help minimize the effectiveness of the play, such as the scrape exchange. The midline read combats many of those counters, because both of the defenders involved in the scrape exchange are now blocked.

The midline read also gives the offense increased flexibility in who they read. Perhaps the most significant benefit of the zone read is that the offense can potentially block one of the defense’s best players without even touching him. But what if that defense has a dominant interior player — say Rams defensive tackle Aaron Donald? Rather than trying to block him play after play with an overmatched guard, read him. This puts an interior player, used to having bodies all around him, in conflict in space and out of his comfort zone.

Just like defenses defend great quarterbacks by changing up their looks and trying to be unpredictable, the midline read is a tool that allows offenses to do the same thing with a dominant defensive lineman.

RB Motion

Chip has several disguises to hide his true intentions in the run game. Beyond making the alignment of his running back more homogeneous across his base run plays and having variations that set the play side to the same side as the back, Kelly also uses motion to his advantage.

Many defenses will set their strength away from the running back’s alignment when facing shotgun-based ground attacks. When Kelly sees that happening, or when he simply wants to run against a specific look the defense is showing on the backside, he will motion his running back to the opposite side of the quarterback just before snapping the ball. Because the motion occurs at the last possible second, defenses often don’t have enough time to adjust and Kelly is able to run his preferred play into a more advantageous look for his offensive lineman.

Tackle-Over

We haven’t spent much time discussing how Kelly uses different formations to enhance his run game, but Kelly does several things in this area to mess with the defense’s gap control. Most notably, Kelly frequently utilizes unbalanced offensive lines.

Kelly’s preferred flavor of the unbalanced offensive line is the "tackle-over," in which (and this is really going to surprise you) one of the tackles moves over to the opposite side of the line and a tight end replaces him next to the guard.

Unbalanced lines can create several potential problems for the defense if not properly identified. If the defense fails to recognize the unbalanced line — and while that task should be straightforward, it’s more difficult to do so at the up-tempo pace Kelly’s offense operates at — it can lead to breakdowns in the defense’s run fits, potentially leaving a gap unaccounted for.

By pairing an unbalanced line with trips to the opposite side, as Kelly will often do, the defense is faced with a unique problem. On one side of the formation, the tackle-over side, is the run strength, which features no eligible receiving threats. On the other side, the trips side, is the pass strength, which features four receiving options.

At this point, most defenses will respond by moving their support defenders (either a cornerback or safety) over to the trips side. This potentially leaves them light on the tackle-over side of the formation, giving the offense an advantage in the run game.

Kelly doesn’t only run to the tackle-over side when utilizing formations with unbalanced lines, which keeps the defense from overloading their front to that side. But pairing an unbalanced line with trips to the opposite side is just one example of how Kelly uses formations to mess with the defense’s gap control and put his offensive lineman in advantageous positions.