Reel-to-Reel: A Look at Shanahan's Minor Play Variations in the 49ers' Week 4 Victory
Whatever slow-start millstone that had been cursed upon head coach Kyle Shanahan has now been broken. The undefeated San Francisco 49ers dominated the Arizona Cardinals in Week 4, scoring touchdowns in five of its seven possessions and racking up 395 yards of offense.
The 49ers are firing on nearly all cylinders, minus the defense allowing a 99-yard touchdown drive in the second half.
The 49ers' offense played nearly flawless football, allowing only three total pressures of any kind and not committing a single penalty. Indeed, there is always room for a deeper look into some of quarterback Brock Purdy's throws – such as timing and ball placement – but those are for more intelligent people.
These are good times we're living in, Bubba. And if what we're watching in Santa Clara is still not hitting your expectations, remember the dark years of Dennis Erickson and the doormat salesman from Pennsylvania. I'm chalking up Purdy's near-perfect stat line as a reason to set objectivity aside and celebrate. It was an impressive feat.
One dominating theme from Sunday's win was Shanahan's variations on some of his staple plays, which you will find below.
1st Quarter – 1 & 10 at the SF 38 (13:23)
Shanahan opened the game by calling 'F Fly to North Left Clamp F Left 17 Power.' If you've been following my work, you know this is a standard gap run in every playbook from youth football to the professional level.
The play foreshadowed running back Christian McCaffrey's rushing onslaught.
Throughout the afternoon, Shanahan attacked the Arizona defense with a heavy dose of gap runs and inside zone. Running back Christian McCaffrey was able to carve his way through the narrow running lanes and gain chunk yardage throughout the game.
Also, Arizona did not adjust its defense to counter the run. They remained in a 3-man front for most of the game, shifting to a 4-man line in certain situations. I am unclear why Arizona did not adjust, but it worked in the 49ers' favor.
Above is a balanced 3-4 front with a double guard bubble. Both defensive tackles would adjust their alignment from play to play, but this was the typical front the 49ers' offense faced in Week 4.
1st Quarter – 1st & 10 at the ARI 42 (11:42)
On the opening drive, Shanahan called a 'Drift-Swirl' concept that gained 16 yards. As discussed in previous work, 'Drift' is one of the most reliable plays in the 49ers' playbook.
Usually, a 'drift' concept has two receivers, the first being the 'drift' route and the second being any intermediate or deep route on the tree. In this instance, Shanahan called 'swirl,' which has a receiver run a stem to 10 yards, break toward the corner for 5 yards, then plant, spinning outside and working back toward the quarterback.
‘Drift' can use any play-action protection. Since Shanahan opened the game with a power run, he called 'drift-swirl' using the same run action up front.
Arizona linebacker Kyzir White took a four-step read to honor the fake, which opened a window for Purdy to hit Aiyuk for a 16-yard gain.
2nd Quarter – 1 & 10 at the SF 36 (7:43)
Midway through the 2nd quarter, Shanahan called in a play with all the look of 'X-Rider' but missed a few key elements.
‘Rider' is a Yankee concept that Shanahan has called for over a decade. It is a two-man route combination, utilizing play-action to freeze the linebackers and seven-man protection because it is a slow-developing play.
However, this play did not use any play-action, and wide receiver Brandon Aiyuk's route looked more like 'deep-thru' rather than a streak. It is in the realm of possibility that Purdy made these modifications in the huddle, or maybe he bailed on the play-action because he saw that Arizona's coverage was ideal for a deep shot.
And again, you'll note another 33 front from Arizona, with the defensive tackles showing minor adjustments from the game's opening play.
3rd Quarter – 1 & 10 at the SF 25 (4:12)
The 49ers needed a spark after Arizona drove the field's length for a touchdown. Shanahan called in a 'Heat' concept, a play I rarely see.
'Heat' is similar to 'rider' as it is a two-man route combination that uses play-action. The primary read for the quarterback is the receiver running a 'Miami' route, which sells a high cross, but the receiver sits down once he hits the hash. The second receiver in the pass progression is usually the fullback, who ends up in the flat after executing a fake block.
The 'field post' is an alert and can be the option if the safety bites hard on the 'Miami' route.
Once Purdy executed the run fake and hit the top of his drop, it was clear he would take a deep shot to Aiyuk. Arizona safety Jalen Thompson turned his hips parallel to the sideline, assuming Aiyuk would continue to streak upfield.
But at the same time, Aiyuk planted and cut across the field in unison with Purdy's release. It was a perfect play and set the 49ers up for another touchdown seven plays later.
The undefeated 49ers are dominating games, so the usual suspects who deem Shanahan's offense as 'vanilla' are silent. But Shanahan has a way of continuing to change even his staple plays to give each a fresh look and confuse a defense. I expect more of that this coming weekend against the Dallas Cowboys.
A few weeks ago, I heard former 49ers Richard Sherman describe the 49ers' rivalry with the Dallas Cowboys as 'old hate.' It was an accurate observation that struck me to the depths of my icy core.
It is an old hate that burns from sell-out youngsters in the early 1990s showing up to school in brand-new Cowboys gear after a Super Bowl win.
No, you didn't have an uncle in Texas who just happened to buy that for you after Super Bowl XXVII. You purchased that on your own, willingly selling your blackened soul to Jerry Jones for a few scraps of silver and emblazoned that hideous star upon your brow.
This Sunday, the only thing that matters to me is a victory over Dallas. I don't care who scores; I don't care about a pass chart, average yardage per attempt, or if McCaffrey runs the ball 25 times.
The only thing that matters is to bury those frauds from Texas.
All statistics courtesy of Pro Football Reference unless noted.
All images and video clips courtesy of NFL.com.