Shortly after Eagles coach Nick Sirianni and his assistants trickled into the team facility Tuesday morning, offensive coordinator Shane Steichen held his own briefing in a conference room at NovaCare Complex.

Gathered around the room were defensive coordinator Jonathan Gannon and a majority of the defensive assistant coaches. With their ears perked, Gannon and Co. carefully listened as Steichen offered his insight on their upcoming opponent: quarterback Justin Herbert, with whom he worked closely last year as the Chargers’ offensive coordinator.

“[Steichen was] awesome, awesome,” Gannon said Tuesday afternoon. “Big-time. ... Anybody we play, there’s no stone unturned. If we can get a little bit of information or try to figure out a little bit of a why.

“We pick people’s brains and try to gather information. But ultimately when we started watching them yesterday, [we ask ourselves] ‘All right, let’s watch what they’re doing, see what they do well. See how we have to defend them.’ All that stuff. So we use all the information we can.”

The Eagles are coming off their best defensive performance under Gannon, who succeeded Jim Schwartz in the offseason. The defense forced a season-high 10 quarterback hits and six sacks while limiting the Lions to just six points in the Week 8 road victory at Detroit. Most notably, Gannon dialed up more challenge plays between his willingness to blitz at a higher rate and incorporate different coverage packages.

“The D-line dominated in the run and pass game,” Gannon said. “We got to a lot of second- and third-down known pass situations and made it a tough day for Detroit.”

Ahead of the Eagles’ upcoming Week 9 home game against the Chargers on Sunday, Gannon peppered Steichen with questions about Herbert’s tendencies.

The Chargers (4-3) are in second place in the AFC West. They’re riding a two-game losing streak, but they’ve shown glimpses of being much better than their record suggests.

Last season, Herbert rewrote history books and was named Offensive Rookie of the Year after being drafted No. 6 overall. Herbert recorded the most total touchdowns (36), most passing touchdowns (31), most completions (396), and most 300-yard passing games (eight) by a rookie quarterback.

“[Steichen told me], ‘This is what Herbert does really well and this is what we were trying to improve with him,’” Gannon recalled of their conversation. “‘These are the looks that he likes. This is how he wants to play.’ Just with any quarterback, what is he comfortable doing, and what can we try to do to make him uncomfortable?”

Said Steichen of Herbert: “He’s a heck of a football player, bottom line. He’s big [6-foot-6, 237 pounds], he’s got a huge arm, he can stand in the pocket. That’s one of the biggest things I learned from being around him. He’s able to stand in there when the blitz is coming and he can take hits, stand there and deliver the throws. He’s smart, he’s intelligent. He gets the ball out of his hands.

“You’ll see on tape, a lot of times he’s hitting his back foot and boom! He’s getting the ball to the check-down quickly. He has accelerated vision. Can do it all. Heck of a football player.”

Steichen noticed Herbert’s impressive talent early during his rookie season.

“You saw the physical ability, without a doubt, him throwing,” Steichen said. “You always want to know what it’s going to look like when he gets in a game. Each week he would do something that was like, ‘Holy crap, that was pretty impressive.’ And he continued to do that week in, week out. And he’s been playing good football again this year.”

Besides Steichen, there’s plenty of familiarity between the Eagles and Chargers coaching staffs. Gannon considers Chargers coach Brandon Staley a best friend; they grew up together in Ohio and they were part of each other’s weddings. Sirianni worked in multiple capacities for the Chargers from 2013-17; he started as an offensive quality control coach before becoming quarterbacks coach and later wide receivers coach.

“There’s a lot of weapons with those guys,” Steichen said. “I’ve been giving my insight on those guys’ abilities and obviously Justin Herbert. It’s going to be a heck of a challenge. We know we’ll have our hands full.”