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There is no group within any sport whose success is as dependent on effective communication as the offensive line in football. Physical skill and effort can make a great runner or receiver, but when five or six of us are involved, no amount of talent can replace the ability to understand one another.
Bill Walsh. 1985 San Francisco 49ers Playbook.

We have reached the point in the professional football offseason where experts and hack writers flood fans with speculative commentary. I often wonder when the mock drafts and trades get old, but apparently, the kids love it.

Maybe there are a few of you floating around the ether bored to tears with the guess-the-win-total for the 2020 San Francisco 49ers. Frankly, all fans should want more than reading about an untested hypothesis.

To truly dive into football at any level, it helps to watch the tape to know what you're seeing. For you, Curious Reader, I will bring you a series of articles breaking down the terminology and why a pass protection, run, or route combination worked.

Let us go then, you and I, through the deserted streets and busy internet and break through the bounds of average fandom. By the time the regular season rolls around, your powers will far exceed those of mortal men.

A non-football person may look at a pass play and see it as an overly violent game of catch. After all, how hard could it be to merely block the defender in front of you?

Pass protections in any offense are loaded with microscopic nuances. 2/3 Jet protection, one of the primary protections used in head coach Kyle Shanahan's offense, changes depending on the defensive front. The reads and responsibility of each man can alter slightly because the Mike linebacker is shifted too far left or because a defensive lineman is in a 1-technique, rather than a 3i-technique.

The origins of 2/3 Jet can be traced back as far as 1982 when the late Bill Walsh introduced 'slide' protection in his 1982 playbook. Today's version looks nothing like Walsh initially drew it.

Walsh's early version of 'slide' was used primarily in the 0-1 holes. The center and left guard would work different blocks against different fronts with both backs flowing to the right. Against a standard 4-3 front, the center would block the defensive tackle to his left while the guard had his eyes on the Will backer. The left guard could also pop out to pick up the Will linebacker if he shot around the left edge. The fullback would shore up the A-gap on the right side, with the halfback flowing to the right edge of the line of scrimmage.

In the 49ers 1985 playbook, Walsh introduced 'slide' again, but his modifications resulted in a protection that looked more like today's version of 2/3 Jet. It was gap blocking, and Walsh noted that it should be used "when blitz or dog is obvious."

Where and how 'slide' protection morphed into a 2/3 Jet is probably in a playbook sitting in a hot, dusty attic. While head coach of the Oakland Raiders, Jon Gruden, had 2/3 Jet in his playbook and listed it as the offense's primary pass protection. I am assuming that Shanahan picked it up while working as an offensive quality control coach with the Tampa Bay Buccaneers.

Shanahan uses 2/3 Jet protection, much as Gruden did. It is a slide protection that sends four offensive linemen away from the call, with the tackle and back protecting the opposite edge.

Week 2 – 2nd Quarter: 2nd and 20 at the SF 15 (14:15)

'Burner' has been a play in Shanahan's book for many seasons. It is an explosive play that can catch a defense flat-footed. It made sense for Shanahan to call 'burner' when the 49ers were stuck at their 15-yard line.

Unfortunately, quarterback Jimmy Garoppolo threw an interception to Cincinnati Bengals' cornerback William Jackson. But we can ignore the error and instead focus on the 300 Jet protection. 300 Jet told the offensive line to slide to the strong side, leaving tackle Joe Staley and running back Raheem Mostert to pick up the weakside edge.

Cincinnati showed a 42T front, or four defensive linemen and two linebackers. Jet protection tells the blocking back to read inside to outside, starting at the center. Therefore, Mostert's first look was the Mike linebacker, and the second was the nickel defensive back.

Jet protection does not force the back to remain in the backfield for the play's lifespan. Since neither the Mike nor the nickel defensive back blitzed, Mostert entered the play on a swing route.

Week 5 – 3rd Quarter: 1st and 10 at the SF 10 (14:59)

The term 'Omaha' and football pair together like a plate of Buffalo wings and 29-degree draft beer. Former quarterback Peyton Manning made the 'Omaha' call famous a few years ago, but it has been a fixture in football terminology for decades.

In the modern West Coast system, double or even triple out-routes are called 'Omaha.' Walsh and former 49ers offensive coordinator Mike Holmgren had a similar play in their books, but called it 'double outs' or 'double square outs.' We can thank Mike Shanahan, 49ers offensive coordinator from 1992-1994, for boiling the combination down one keyword: Omaha.

Kyle Shanahan called '200/300 Jet Omaha' throughout the 2019 season. Quick out routes and slants are the embodiment of the West Coast Offense. These precise short routes, in harmony with the quarterback's footwork, are essentially long runs that can quickly gain six or eight yards.

When Jet protection is called with a two-back set, one back has a free release – called 'scat' – leaving the other with pass protection duties.

On this play, running back Matt Breida had a free release and fullback Kyle Juszczyk was helping his offensive line pick up blitzing Browns.

Against a 55 front, Juszczyk made his protection read inside-out, starting at the center. That meant his first read was the Will linebacker, and the second was the free safety. Oddly, Juszczyk never looked at the Will and bolted immediately to his left. It's possible Juszczyk added in the deception to the play to freeze the Will linebacker.

Week 13 – 3rd Quarter: 3rd and 4 at the SF 7 (:17)

'Lion' is a route combination term that dates back at least to Gruden's 1998 Oakland Raiders, if not further. It tells two receivers to run mirrored slant routes. The elder Shanahan ran 200 Jet Lion as coach of the Denver Broncos, and it should be no surprise that his son now runs it in San Francisco.

In the play above, the Ravens defense was in a 33 front. As with all Jet protections, Mostert was to read inside-out, starting at the center. But note the position of the Mike linebacker. He was outside shade of the center, making this a one-read block for Mostert. He darted right at the Sam backer, made an excellent block, allowing wide receiver Emmanuel Sanders gain 12 yards on the play.

Jet protection is not new to the 49ers or a proprietary strategy patented by the Shanahan family. Former 49er head coach Jim Harbaugh used it during his tenure and expanded the concept into seven-man protection. I'd be willing to bet Los Angeles Rams head coach Sean McVay uses Jet as well.

Next time, we'll dive into the 20 series – its origins and how it works today in a faster, spread out game.

All statistics courtesy of Pro Football Reference.
All images courtesy of
  • Bret Rumbeck
  • Written by:
    Bret Rumbeck has been writing about the 49ers since 2017 for 49ers Webzone and 49ers Hub. He is a Turlock, CA native, and has worked for two members of the US House of Representatives and one US Senator. When not breaking down game film, Bret spends his time seeking out various forms of heavy metal. Feel free to follow him or direct inquiries to @brumbeck.