Football is a sport bound together and upheld by family trees.

In rare cases — the Shanahans, the Harbaughs — these trees are rooted in biology. More often, they grow from coaching relationships — a shared mentor, long years spent side by side on the same staff, belief in the same tactics and philosophies.

And then we get a game such as Monday night’s showdown between the Ravens and the Los Angeles Chargers, which will bring two branches of the same tree into sharp conflict.

The headlines begin with the brothers atop these two AFC contenders. John and Jim Harbaugh have not coached against one another since Super Bowl 47, 12 years ago.

With Jim in the college ranks and John still in the NFL, it was easy for them to maintain a mutual support network, even shipping developing coaches back and forth from Ann Arbor, Michigan, to Baltimore.Now, the brothers are back to chasing the same prize, and a passel of those coaches, executives and players who cut their teeth with the Ravens will be on the other side. It’s an important game for the Ravens as they try to bounce back from an error-filled loss to the Pittsburgh Steelers and maintain a foothold in the AFC North race. To win it, they’ll have to overcome the one opponent most built in their image.

“We’ve been joking that it’s going to be like playing the L.A. Ravens,” fullback Pat Ricard said.

A not-so-quick rundown of the Chargers’ Baltimore connections:

General manager Joe Hortiz spent the first 25 years of his career with the Ravens, learning how to build a roster first from Ozzie Newsome and then from Eric DeCosta.

Offensive coordinator Greg Roman held the same position with the Ravens from 2019 to 2022, laying the framework for Lamar Jackson’s first NFL Most Valuable Player season.

Defensive coordinator Jesse Minter coached on the Ravens’ staff from 2017 to 2020, right beside his Baltimore counterpart, Zach Orr.

No. 1 and No. 2 running backs J.K. Dobbins and Gus Edwards held the same positions on the Ravens as recently as the beginning of last season.

Reserve tight end Hayden Hurst was the Ravens’ first first-round draft pick in 2018, the year they traded into the last spot of that round to select Jackson. Starting center Bradley Bozeman was Baltimore’s sixth-round pick the same year.

The ties that bind indeed.

There are tactical concerns at play with such familiarity.

We’ll get to those.

But Mark Andrews, who became a star in Roman’s tight end-friendly offense, pointed out that Monday night’s game will also be an unusual chance to celebrate the NFL roots reaching out from Baltimore.

“I think it’s definitely a unique thing,” Andrews said. “I think it’s a tribute to the culture that we have here and just the type of organization that we have. We’ve had a bunch of incredible players and people and personnel that [are] on [the Chargers] and are doing great things. So it’s cool.”

The Chargers (7-3) freely acknowledge the Baltimore influence on their franchise as they reset from a dispiriting 5-12 season under previous coach Brandon Staley.

“Down throughout the roster, it’s kind of what we’re driving for,” Jim Harbaugh told the “Rich Eisen Show.” “When you watch the Ravens or watch our team, we hope to be looking in the mirror. That’s how much respect we have for the Baltimore Ravens.”

John Harbaugh said he already sees his brother’s touch, and by extension those of all those other Ravens, in everything the Chargers do.

“The culture, the way things are done, how they play, the schemes are very similar,” he said. “Not exactly the same but in a lot of ways, mirror images. With that, it’s two different football teams. It’s two teams squaring off in a really important game. That’s really what it’s going to be about, the guys out there playing the game.”

So, is it harder to trick your mirror image when constructing a game plan?

Players and coaches usually downplay the impact of having a former colleague embedded with a rival. In this case, however, several Chargers were intimately involved in designing the Ravens’ roster and strategy.

Minter is four years and two defensive coordinators removed from his time in Baltimore.

But Roman worked closely with Jackson and many other key offensive players, and Hortiz scouted most of the Ravens’ roster. Dobbins and Edwards played in coordinator Todd Monken’s offense a year ago.

John Harbaugh said he couldn’t remember a game in which he faced two coordinators who’d worked for him.

“It’s different than other games, sure,” he said. “We know the schemes pretty much. But there will be wrinkles. It’s the old ‘they know what we know that we know that they know that we know that they know what we know.’ With that, there will be wrinkles. But it’s going to come down, in the end, to the players. All the scheme stuff is important, but most important is really how the game is played.”

The Ravens don’t seem concerned about the Chargers having inside knowledge of their playbook.

“Teams see everything we do on film anyway,” Ricard said. “The thing they know is us personally.”

For all the acclaim around quarterback Justin Herbert’s efficient performance in Jim Harbaugh and Roman’s system, Minter’s defense has been the unexpected star, going from 24th in points allowed last season to first this season.

The Chargers are doing it without a signature element. They deceive with ever-changing coverages, get to the quarterback without relying on all-out blitzes and take the ball away, much like the Ravens did last year.

On offense, Roman can’t use all the run designs he developed for Jackson, but Ravens defenders see plenty that’s familiar when they peruse Chargers film.

“It’s two like-minded teams,” safety Kyle Hamilton said.

“It is somewhat similar. You don’t have the same people. You don’t have Lamar. … It’s hard-nosed football. You know where the ball’s going. You know what’s going to happen. It’s can you stop it or not? There’s some beauty in that.”

Have a news tip? Contact Childs Walker at daviwalker@baltsun.com, 410-332-6893 and x.com/ChildsWalker.