A year ago about this time, Matthews was 18 and skating in suburban Detroit, preparing to play for the United States at the World Championship. He went to Joe Louis Arena to watch the Detroit Red Wings play the Tampa Bay Lightning in the Eastern Conference First Round. He sat in the stands. No one recognized him.
And in June, Matthews attended the Stanley Cup Final at SAP Center with some other top 2016 NHL Draft prospects. He watched the Pittsburgh Penguins defeat the San Jose Sharks 3-1 in Game 4.
"It's the best hockey," Matthews said. "It's definitely a lot of fun to watch, and I'm sure it's a lot of fun to play in too."
Now he'll get to find out, and we'll get to watch him.
Matthews, 19, the No. 1 pick in the 2016 Draft, will headline an outstanding group of rookies debuting in the Stanley Cup Playoffs. These young players won't be easing into the experience. They'll be difference-makers and key role players.
Goaltender Matt Murray won 15 playoff games as the Penguins won the Stanley Cup last season, tying the rookie record held by Patrick Roy, Ron Hextall and Cam Ward. He's 22 and still a rookie, just like teammate Jake Guentzel, who has emerged as an impact player up front.
Forward Matthew Tkachuk, 19, plays a top-six role for the Calgary Flames, showing skill and bite like his father, Keith, did in an 18-year NHL career than included 89 playoff games.
Defenseman Zach Werenski, 19, moves the puck and quarterbacks the power play for the Columbus Blue Jackets, helping make them one of the best teams in the League in the regular season. He sustained a shoulder injury late in the regular season but is expected to play in Game 1 of the Eastern Conference First Round against the Penguins at PPG Paints Arena on Wednesday (7:30 p.m. ET; USA, SN 360, TVA Sports).
Defenseman Brady Skjei has shown he can put up points for the New York Rangers.
The Chicago Blackhawks dressed nine rookies while winning the Western Conference and will count on some in the playoffs: Nick Schmaltz, 21, and Ryan Hartman, 22, as top-nine forwards; Tanner Kero, 24, as a checking-line center; and Michal Kempny, 26, as a depth defenseman.
But no team will count on rookies more than the Maple Leafs, who also played nine rookies, with six playing at least 77 games.
Matthews led NHL rookies in goals (40) and points (69). He set single-season records for goals by a United States-born rookie and for goals and points by a Toronto rookie.
Forwards Mitchell Marner, 19, and William Nylander, 20, were close behind. Marner (19 goals, 42 assists) and Nylander (22 goals, 39 assists) finished tied for third among rookies with 61 points.
The Maple Leafs had three others ranked 19th or better among rookie scorers: defenseman Nikita Zaitsev (36 points), forward Connor Brown (36) and forward Zach Hyman (28).
"They're putting a lot on themselves to produce and make a difference," Maple Leafs center Brian Boyle said. "They're not being coddled. They're not saying, 'Oh, it's just my first year.' These guys demand the puck."
Your first experience in the Stanley Cup Playoffs can be startling. No matter how much you watched from the stands, no matter how much you watched on TV, no matter how much you heard about it, you don't understand the speed and intensity until you experience it yourself.
"I was like, 'Holy crap, it's different hockey,' " said Red Wings forward Dylan Larkin, who played in the postseason as a 19-year-old rookie last season. "But you'll see the real players will come through, and you'll be able to see who's going to put the team on their back, who's going to shy away. It's a great time to see who's a man and who's a boy, I guess."
Boyle wasn't a rookie when he experienced the playoffs for the first time. He was in his fourth NHL season when he went with the Rangers in 2011. Still, he was so excited, even after it was over.
"I was like, 'Wow, that was the most fun hockey I've ever played. We've got to get back there,' " Boyle said. "It's like, 'We played pretty well.' "
And the Rangers lost to the Washington Capitals in five games.
"The most important thing is how much fun it is and to not get overly emotional early on," Boyle said. "The first round's kind of … It feels like a sprint. It's just a slugfest right away, and you've got to understand you've got to continue to play with principles. Use your emotion to your benefit. Play hard. But don't let it get the best of you. You're playing to win games, and that's ultimately the only thing that matters."
For the Maple Leafs, the good news is that nothing has seemed too big for Matthews yet. He scored four goals in his NHL debut. His personality didn't change during hot and cold streaks, even amid the media attention in Toronto.
Video: TOR@DET: Matthews nets second, reaches new milestone
The other rookies have taken a businesslike approach too. General manager Lou Lamoriello and coach Mike Babcock have made sure of that. And the rookies played playoff-type games down the stretch.
"They're talented," Lamoriello said. "They've had success wherever they've been individually. Now they're really understanding and realizing what it takes to have team success, and that's really sometimes doing things you don't like to do or doing things for your teammate and sacrificing individual aspects for collectively, because that's what the playoffs are all about.
"We're trying to build something that can be sustained. You can't get ahead of yourself. Because you have a little bit of success, you can't think you're there. Other people can do that if they want, but you can't allow it to become within yourself or within your team because that's not going to help.
"Someone might have different levels of abilities, but it's the mindset that's within that that has to be under control. That mindset, it's been very consistent, and that's the building of something special."