Think about a 3rd and 6, middle of the field, the San Francisco 49ers are with the ball. They are in 21 personnel, with running back Christian McCaffrey and fullback Kyle Juszczyk on the field. The formation also has tight end George Kittle, wide receivers Brandon Aiyuk and Deebo Samuel. Suddenly, all of them get open, with an empty formation. And even worse: Kittle, Juszczyk, and McCaffrey are wide, while Aiyuk and Samuel are closer to the offensive line.

On defense, the Packers have the option to work with zone. But then Jaire Alexander and Carrington Valentine will cover Kittle and Juszczyk, while linebackers Quay Walker and De'Vondre Campbell will have to be around Aiyuk and Samuel. If they go man coverage, McCaffrey and Kittle will be covered by these linebackers out wide. It doesn't matter what you do, it's a mismatch. As NFL Producer for CBS and Amazon Prime Ben Fennell says, it's a schematic nightmare.

The 49ers have the tightest average formation in the NFL in 2023 — 19.9 yards, according to Next Gen Stats. At the same time, they use an empty formation 11% of the time, the sixth highest number in the league. And that kind of formation, empty, is what eventually forces the Packers edge rushers to drop into coverage against receivers — you certainly remember Preston Smith trying to cover Davante Adams against the Las Vegas Raiders, right?

How do you stop them?

"Thirty one defensive coordinators are asking the same questions," Ben Fennell said. "They have incredible two-way players that make them equally threatening against tight formations and spread them out formations."

Ideal scenario

The two defenses that gave Kyle Shanahan the most problems have been the Cleveland Browns and the Baltimore Ravens. While teams usually go with base personnel to stop the run as a priority, both teams used some version of nickel. The Browns, for example, had five defensive backs on the field on 76.5% of the snaps — at that point of the season, the average of nickel package against the 49ers was 11.1%.

The 49ers lost 19-17, and Brock Purdy completed only 12 of 27 passes for 125 yards, a touchdown, and an interception.

The Baltimore Ravens prefer to use a big nickel formation, with three-safety looks. After all, they have Kyle Hamilton, Marcus Williams, and Geno Stone. If the 49ers have their two-way players, the Ravens do as well. If the 49ers like to do motion to get the defense confused, the Ravens can do a lot of pre-snap disguises and post-snap changes of the picture, and their personnel is effective to limit what San Francisco wants to execute.

That's how Baltimore limited them to 19 points.

But there's a problem: Green Bay doesn't have the perfect personnel to do that.

What's their options

The Packers lost an important piece of their secondary, as Rudy Ford is on injured reserve with a hamstring injury. If defensive coordinator Joe Barry decides to mimic the Ravens with three-safety looks, Darnell Savage would execute Kyle Hamilton's role in the slot and closer to the line of scrimmage. But that would force the Packers to use Jonathan Owens and rookie Anthony Johnson Jr. deep.

Green Bay has used nickel a lot, but not big nickel. Slot cornerback Keisean Nixon is the fifth defensive back on the field — but he is a short player, and a big mismatch if the 49ers put Kittle, for example, on him.

If the Packers go with base defense, there are multiple layers. First, third linebacker Isaiah McDuffie injured his neck during the Dallas Cowboys game. If he can go, a combination of Quay Walker, De'Vondre Campbell, and McDuffie is a decent group of players, but Shanahan will certainly find a way to exploit them in coverage.

What can the Packers do?

Schematically, it's a hard question, because the Packers don't have the horses to run what ideally would be able to limit the 49ers. Cover 6 is probably the most logical answer. So, for Ben Fennell, it's much more about execution.

"The 49ers are simultaneously in 11, 12, 13 personnel. It's a nightmare," he mentioned. "Get lined up, don't let motion create busts, stop the run on first down. Tackle, tackle, tackle, and avoid over the top pass plays. It sounds so simple, but these are the expectations."

The Packers are traveling to face The Avengers. And their ability to limit their production and efficiency is a key to allow Jordan Love and the offense to have a realistic chance.

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