DETROIT — Kasperi Kapanen isn’t just down a teammate because of William Nylander’s ongoing contract dispute with the Toronto Maple Leafs.

He’s without his roommate and best friend.

“When we’re together, we’re like brothers,” Kapanen said Thursday before the Leafs faced the Detroit Red Wings. “It’s fun to have somebody in Toronto who I can bond with. We fight and we f— around and piss each other off, but at the end of the day we love each other.”

The sons of former NHLers shared an apartment in Toronto the last two seasons and labelled their friendship a “bromance” in social media posts. They played together in the American Hockey League before graduating to the Leafs.

Now, they’re on hiatus.

Kapanen has basically cut off communication with Nylander in recent weeks. He decided that it might be a bother if he reached out to his buddy while he was skating alone back in Stockholm and waiting for an end to his contract impasse.

It is a touch ironic, then, that Kapanen’s best opportunity as an NHL player can be tied directly to Nylander’s absence from the team. He’s basically taken his position in the lineup.

Kapanen was elevated to Auston Matthews’s right wing during Sunday’s game in Chicago and produced a goal and an assist within three shifts. He added two more assists while playing with Matthews and Patrick Marleau in Dallas on Tuesday — giving him more helpers in five periods (three) than he’d managed in his previous 68 NHL games (two).

What’s more, the 22-year-old Finn made plays against high-end opponents to get them. He pressured Duncan Keith and stole the puck off the two-time Norris Trophy winner before finding Matthews against the Blackhawks and got positioning on Alexander Radulov to set him up again in Dallas.

“Really nice play by him,” said Matthews.

This kind of chance has been a long time coming for Kapanen, a 22nd-overall pick by Pittsburgh who is entering his fourth season in Toronto.

Until now, he’s rarely played above the fourth line while with the Leafs. But with the departure of veteran wingers Leo Komarov and James van Riemsdyk over the summer — not to mention Nylander’s absence — the door has swung wide open for him.

Mike Babcock is urging Kapanen to use his most dangerous weapon, his speed, to follow Zach Hyman’s path to success. That is, become the grinder on a skill line — the kind of player who can win back pucks and get them to the elite finishers.

“He’s got to understand what kind of player he’s going to be in the National Hockey League. I think that’s the hardest thing when you enter the league and you’re not a top two-line player,” said Babcock. “You’ve been a top two-line player your whole life and now you’ve got to find a way to survive, and you’ve got to find a way to be important on a team. So, his way is going to be with his speed, with his tenacity, with his heavy play, with on the cycle, with finishing checks, with getting to the net. And the sooner the player understands that — no matter what the coach says, the player’s got to come to grips with what they’ve got to do to be successful in the league.

“And when they do, they usually get up and rolling. He’s been in the grinder now. You’re a first-round pick, it takes this long to get here. Now it’s time for him to go.”

Kapanen has spoken a fair bit with Matthews and Marleau in recent days, trying to gain a better understanding of where they’ll be in the offensive zone. He doesn’t know how long he’ll be afforded this opportunity from Babcock and wants to use it to make a strong impression.

In recent years, he’s added penalty-killing duties and more defensive awareness to his repertoire while carving out a spot in the NHL, but this assignment more closely resembles what got him drafted highly to begin with.

“It’s fun to get that responsibility playing with those guys,” said Kapanen. “You know, just in general, I’ve felt better. I felt like my legs have been pretty good. Obviously playing with Matty and Patty, it’s special for sure. I mean they’re two amazing players and it’s pretty easy to play with them.”

Kapanen has moved into his own apartment in Toronto and doesn’t expect Nylander to join him once he signs a new contract. But he’d love to see his good buddy get back to the city soon, even though he’ll likely have to give up one of the most coveted spots in the Leafs lineup when it happens.

“I’ve been pretty quiet with him. I know he’s going through a lot right now so I’m giving him his space,” said Kapanen. “I miss the guy, he’s pretty much my best friend here, and I haven’t seen him in a long time.”