TORONTO -- The cellphones of several Toronto Maple Leafs prospects rang Sunday night with calls from team management.

William Nylander, Kasperi Kapanen, Zach Hyman and Nikita Soshnikov were all told to prepare for their NHL debuts Monday night against the Tampa Bay Lightning at the Air Canada Centre.

The youth movement is officially underway in Toronto.

General manager Lou Lamoriello said it was the club's plan all along to recall the likes of Nylander and Kapanen following the trade deadline with the intent of giving those prospects a real taste of the NHL.

"They need that type of experience," Lamoriello said shortly after the 3 p.m. ET deadline. "They need to get their feet wet.

"They need to feel comfortable and when they come to training camp next year they'll know what's in front of them, how they prepare this summer - they'll know what they have to do. It's the right thing."

Leafs coach Mike Babcock is excited to see what some of the club's most promising young talent can deliver. He's been admittedly impressed watching the skill and speed of those formerly with the AHL-leading Marlies, including Nylander with his 45 points in 37 AHL games.

"I want to know who's a real player," Babcock said. "Just because you did it in the American League doesn't mean you're going to do it here.

"I want to know who's got upside and who's got hockey sense and who's got determination and who lives right, who's going to be a Maple Leaf for a period of time and who's not."

Babcock said the last time he coached a team with so much youth was in his junior days with the Spokane Chiefs.

Nylander and Kapanen are both 19. Hyman is 23 and Soshnikov is 22. Also starting in goal is 22-year-old Garret Sparks, backed up by a defence that could include 21-year-old Morgan Rielly, 22-year-old Frankie Corrado and 21-year-old Connor Carrick, acquired from Washington in a trade which sent Daniel Winnik to Washington.

"It's exciting," Babcock said. "You watch them, they're exciting, but they're also kids.

"I'm going to come and watch just like you."

Nylander said he couldn't sleep Sunday night after he got word of his long-awaited recall. The 19-year-old has been eyeing his first NHL game all season, describing it as his only goal.

"It's going to be interesting to see how it unfolds," said Nylander who will wear No. 39 and likely centre a line with Hyman, a Florida draft pick the Leafs landed in a trade last summer.

Nylander and Kapanen were expected to log time together on the power play against the Lightning. Hyman and Soshnikov were expected to kill penalties.

It was to be an immediate test. Tampa has been one of the league's hottest teams, winners in 18 of its past 24 games.

Typically riding to and from the rink together, Nylander and Kapanen only found out the other had been recalled when they arrived Monday morning. It was a pleasant surprise.

Kapanen made sure he immediately alerted his father, Sami, a veteran of 831 NHL games, when he got the news. It was the middle of the night in Finland when the call came through. Despite being sleepy, the elder Kapanen congratulated his son.

Hyman was at home with his family when he got word. He made sure to call his grandparents with the good news.

The Leafs could be dressing as many as 10 players who weren't with them on opening night. Also included are various pieces acquired in recent trades: Carrick, 32-year-old Brooks Laich and 27-year-old Ben Smith.

It's just another step in a roster turnover that began in earnest at this time last year with the trading of veterans like Cody Franson and David Clarkson. The process continued in the summer with the dealing of Phil Kessel and earlier this month with the trading of captain Dion Phaneuf and other veterans.

"We want to set ourselves up for a long run so we're not talking about trading guys at the deadline," said Babcock, "but talking about who we acquired at the deadline. That's our goal."