Adam Fox is in uncharted territory.

Throughout his career, he and Ryan Lindgren formed a defensive duo for the Rangers. They were already familiar with each other from their time in the USA Hockey National Team Development program.

But the Rangers traded Lindgren along with Jimmy Vesey and the rights to unsigned 2021 draft pick Hank Kempf to the Avalanche in exchange for Juuso Parssinen and Calvin de Haan earlier this month.

Fox had been on the injured list for eight games with an upper-body injury and had not yet felt the impact of his longtime friend being dealt away.

He was removed from the injured list last week and played his first two games without Lindgren, losses to the Oilers and Flames.

“It was obviously tough,” Fox said Wednesday. “Someone I played with pretty much my whole NHL career and knew him from before. He’s clearly doing well. I’m not surprised by that. It was kind of weird timing — I was out, so kind of adjusting to it now. Definitely miss him around the room.”

The Avalanche have won six of their seven games since Lindgren joined (6-1-1).

He has a goal and an assist with Colorado and is plus-two on the ice.

Fox was prepared for the trade but also felt it could have been avoided.

Lindgren is an unrestricted free agent after the season.

“I think anyone who is going into that UFA, you have sort of a sense,” Fox said. “Some of that is on us, too. I’m sure if we had a better record and had more of a [playoff] push, he’d still be here.”

In the two games he’s played without Lindgren, Fox has been paired with Urho Vaakanainen.

“I think a lot of times, you only think of lines as forwards and chemistry in that sense, but I think defensemen have to have a lot of chemistry,” Fox said. “Knowing where each other are, communication is huge. You play 300-something games with one guy, you get almost that second sense of where they’re gonna be, where your outlets are, the support, the communication.

“It’s definitely a bit of an adjustment.”

The Rangers held an optional practice Wednesday.

Those who participated were: Fox, de Haan, Vaakanainen, Parssinen, Braden Schneider, Brennan Othmann, Brett Berard, Alexis Lafrenière, Jonny Brodzinski, Will Cuylle, Igor Shesterkin, Jonathan Quick and Carson Soucy.

Soucy, whom the Rangers acquired from the Canucks for a 2025 third-round pick just before the deadline, has been a healthy scratch the past three games.

“I think he’s working to get up to speed on the system,” head coach Peter Laviolette said Wednesday. “Sometimes when you’re thinking a little bit too much, it slows down a little bit. So just getting some practices, watching some games, getting an understanding of how we want to do things, I think will help with that processing speed.”