Last spring, Marner opted not to waive his no-movement clause when the Maple Leafs were negotiating a trade with the Carolina Hurricanes for forward Mikko Rantanen. Marner told NHL.com during the North American Player Media Tour in Henderson, Nevada, in September that one of the reasons for his decision was that his wife, Stephanie, was pregnant with the couple's first child at the time and he wanted to be close to her. In May, the couple welcomed a boy, Miles Daniel Marner.
The fact that the pending unrestricted free agent opted not to sign an extension with the Maple Leafs was yet another reason the fan base seems to have turned on him. Instead, he was shipped to the Golden Knights for forward Nicolas Roy in a sign-and-trade that netted him an eight-year, $96 million contract ($12 million average annual value) with Vegas.
"Mitch got a small taste in Vegas last week of what to expect, which is disappointing," Golden Knights coach Bruce Cassidy told NHL.com of the boos he received from Maple Leafs supporters. "So this game is going to be tough for him. It really is.
"I wasn't around for nine years in that market so I don't know. I just know what I've experienced since he's been here, that his teammates love him and he's been a good player for us. And this is not just another game for our players. They knew how important a game it was to him in Vegas. And they know there will be nothing ordinary about this one. And they are fully behind him."
No one more than Golden Knights forward Jack Eichel, who was booed every time he stepped on the ice during his first game back in Buffalo on March 11, 2022. He had 355 points (139 goals, 216 assists) in 375 games with the Sabres from 2015-21 but was traded to Vegas after a disagreement on how to treat a herniated disk in his neck.
As such, the veteran forward understands what Marner will be going through Friday.
"I mean, it's tough, obviously," Eichel said Thursday, before the Golden Knights played the Boston Bruins. "You have an emotional connection to a place that you spent a lot of time and put a lot into. Nobody ever loves getting a rude welcome back. But at the end of the day, we're here for him and just want to try and support him as much as we can.
"We know it's not going to be easy. But if you know Mitch he's a pretty easygoing guy so I thought he handled the first game with ease. This will be a little more difficult heading back to Toronto and being there, but I think he'll do a great job. And as teammates we're just here for him for whatever he needs and want to try and compete and play as hard as we can to make it a better experience for him."
For many Maple Leafs players, he'll be the enemy on the ice. Off it, he's still a friend to many of them, exchanging texts and laughs to this day.
"Mitch did a lot for this city," Laughton said. "He was a really good player for this team for a while. I was fortunate to play with him for only a short period of time, but he did a lot of good things."
Maple Leafs coach Craig Berube echoed those sentiments.
"Did a lot here for the Leafs as a player and a person," Berube said. "Did a lot for the community and played a lot of good hockey."
To Berube's point about the community: The Marner Assist Foundation raised hundreds of thousands of dollars over the years "to provide assistance in the areas of children's social care, health and education, as well as supporting environmental causes to ensure children have a sustainable future." It also generated funds for causes like London (Ontario) Health Sciences Foundation's First Episode Mood and Anxiety Program (FEMAP), an innovative program providing much-needed access to mental health care for young adults aged 16-25.
As for his performance with Vegas this season, Marner has 52 points (12 goals, 40 assists) in 49 games. Many of those have come in his new role as a center, a position Cassidy said he's becoming more comfortable with after moving there because of a rash of injuries up the middle.
Add it all up, and it undoubtedly will make for an electric, if not polarizing, atmosphere Friday.
"I'm expecting a fantastic crowd," Maple Leafs defenseman Brandon Carlo said. "It's a big game for us in just any regard, but with having Mitch on the other side, just such a key component to this group for a long time, it'll be fun to compete against him. Embrace the challenge.
"He was here for a long time. I hope he just comes in and takes advantage of the opportunity to appreciate all the memories that he's built over his years here.
"There's definitely going to be an extra spring in his step."
NHL.com senior writer Amalie Benjamin contributed to this report