TORONTO -- Players sometimes joke in the Maple Leafs dressing room that Mitch Marner is young enough to be their kid.

One of two teenagers on the Toronto roster, Marner looks even younger than his 19 years off the ice. On it, he and Auston Matthews, also 19, look every bit like ready-made NHL players.

"They're top-five picks," Tyler Bozak, Toronto's 30-year-old veteran centre, said of the duo. "They're unbelievable players for a reason."

Teenagers are no longer all that rare in the NHL today. Twenty-two have already played at least a game and seven have already scored. Almost half the league's 30 teams (14) have at least one teenager and eight teams, including Toronto, have two.

Only a decade ago there were almost none.

In fact, only one teenager played a full season in the 2005-06 campaign: Sidney Crosby. A handful of others saw sparse NHL duty.

Toronto's two teenagers have both looked more than ready to contribute. Matthews, of course, became the first player ever in the modern NHL era to score four goals in his debut. Marner chipped in with his first NHL goal three nights later. He's fired 10 shots in two games and has been, according to Bozak, arguably Toronto's best player.

Leafs coach Mike Babcock believes it's the combination of skill and physical development in today's young players which makes them able to contribute faster than those in the past. Strength coaches, nutritionists, personal trainers and skill gurus are all commonly used by players today, which means they're more prepared to jump in and play right away.

"Major Junior's just NHL-light," said Babcock, formerly head coach of the WHL's Spokane Chiefs and Moose Jaw Warriors. "It's just like light beer, it's the same principle. And the same thing with the NCAA. If you're coached real well in those leagues you're really well-prepared."

While no longer a rare thing, playing in the NHL at such a young age still requires major adjustment, perhaps more so off the ice than on it.

Leafs defenceman Morgan Rielly entered the NHL at age 19 and wasn't so overwhelmed by the hockey, but the realization that the game was no longer just about fun.

"The more overwhelming aspect of it is being 19 and playing with guys that have kids and are buying houses and making investments and that you watched when you were younger," said Rielly, admittedly star-struck in first NHL meetings with Duncan Keith and Drew Doughty.

It was almost like trying to jump from young man to grown man right away, he said.

"I'd probably say the same," said Marner, who won't turn 20 until May. "One of my linemates (Bozak) is engaged and it's kind of crazy joking around with him about that."

Babcock has said that dynamic as inherent in the learning curve for those like Marner, Matthews as well as 20-year-old William Nylander, who had two assists in the Leafs' season opener. Their competition level must continually match that of veterans with families, for whom the stakes might be greater.

The tremendous influx of youth is surely salary cap-related. Young players,who can contribute right away come with cheap entry-level contracts, an effective tool for teams trying to squeeze under the cap. As 31-year-old Matt Hunwick noted, third and fourth lines used to be populated with veterans whereas now "they seem to be being filled more by maybe a younger player, maybe a faster player, or a cheaper player."

A slew of 30-and-over players were tossed overboard by NHL clubs at training camp, including former Leaf P.A. Parenteau, who later joined the New Jersey Devils.

Toronto's teenagers aren't as inexperienced as one might think, according to veteran winger Matt Martin.

Matthews went and lived in a foreign country (Switzlerand) last year, Martin said, while also showing exceptionally well at the World Cup. Marner shined on the Memorial Cup stage. Both have been under the spotlight as top prospects for so long that they've become well-adjusted to being the centre of attention, on the ice and off it.

"It's pretty funny just talking about it and looking at it that way," Marner said of being in the NHL at such at young age. "We joke around with each other a lot about it, saying how I could be some people's kids in the room and stuff.

"It's all fun."