It was Day 1 for Auston Matthews at Toronto Maple Leafs training camp, after the craziness of the World Cup of Hockey and his revelatory play with the under-24 team.

For most of his teammates, this was their first look at his game, up close, in an NHL setting, with coaches barking in their ear. But not for Morgan Rielly, Toronto's top defenceman, who spent the past few weeks on that young guns team getting to know the Leafs' first overall pick, on the ice and off.

Even with that introduction, however, he had a hard time summing up what exactly the big, quiet kid from Scottsdale, Ariz., is bringing to Toronto.

Story continues below advertisement

"His skill and his size," Rielly said when asked what stands out about Matthews. "For me, he's not afraid to try different things. He likes to try to beat people one-on-one. He's a pass-first guy in my opinion. But he's got a great shot. I don't know – I could probably go on for a long time. But I'll probably just end up talking about everything so ... ."

He trailed off.

"I'm looking forward to playing with him," Rielly added.

On Wednesday, the Leafs' first day back from a camp-opening trip to Halifax, the players on Matthews's wings were veterans James van Riemsdyk and Leo Komarov. But Matthews clearly gravitated to some of his fellow young players, goofing around shooting pucks with Mitch Marner – the fourth overall pick in 2015 – and defenceman Andrew Nielsen as the last players on the ice after practice.

At one point, an errant Matthews shot shattered a pane of glass at the end of the rink – the first time, he said, that has happened in all his years on the ice.

He considered it a good omen.

"Lucky day for me I guess," Matthews said.

Story continues below advertisement

Matthews hardly seems like a player who turned 19 less than two weeks ago. Several of his teammates have already commented on his maturity, which was apparent in how easily he handled not only the World Cup, but two large media sessions on his first day at camp.

His answers also offered a hint as to a mature mindset.

Was he nervous, entering his first NHL camp and season? Not really. Mostly excited.

Had he expected to have that kind of impact at the World Cup – scoring two goals and adding an assist while earning a quick promotion from 13th forward to the first line – up against the world's top national teams? Pretty much. Yep.

"Going into it, I knew I could play at that level," Matthews said. "I think the way I played and everything, going into the season here, training camp and preseason, gives me a lot of confidence."

To hear those who know him well tell it, that has never been lacking.

Story continues below advertisement

The interesting thing about Matthews is, the more exposure he gets to the wider hockey world, the more the acknowledgment seems to come that he will be a truly special player. Historically, it hasn't been that way in Toronto. When the Leafs have had a high draft pick in the recent past – say Nazem Kadri or Luke Schenn – they have been thrust too early into an overly bright spotlight and expected to be a saviour, from a young age.

This time, the hyperbole around Matthews doesn't appear to have caught up to his actual talents. He may well be the first Leafs prospect to exceed the hype around his arrival, to be capable of doing more than anyone expected.

So when coach Mike Babcock says Matthews will start the year as the Leafs third-line centre, as he reiterated on Wednesday, he isn't laughed out of the building.

By November, it will likely be clear Matthews is one of the best – if not the best – players on the roster. By then, the discussion might be about the Calder Trophy for rookie of the year.

"I think he'll have a pretty smooth transition right away," said defenceman Jake Gardiner, who marvelled at Matthews's size and how he handled himself on the ice.

"So far he's just living up to the expectations that have been put on him," added Peter Holland, who may well start the year as the team's fourth-line centre given the Leafs' sudden depth up the middle.

Story continues below advertisement

For now, Matthews sounds more worried about acclimating to living in Toronto than acclimating to the NHL. His father, Brian, has moved into the city with him, but Matthews has also found a lot of time to spend with his new teammates tooling around.

Not yet a Blue Jays fan – he's sticking with the Los Angeles Dodgers – he has nonetheless attended a few games as the baseball playoff push energizes the city. And he has been going out for meals and to the mall with Rielly, who at 22, has taken on a big-brother role.

Two of the faces of the franchise are growing together already, with the season opener still two weeks away.

"He's asking lots of questions, but he's smart enough to know what's to come," Rielly said. "He knows what the expectations are for himself. I just tell him the best thing he can do is be himself, have fun and just enjoy playing in the NHL.

"You can tell that he's really happy to be here. For me to hear him speak so positively about Toronto, it's cool. He loves it here. So hopefully he'll be here for a long time."