Charlie McAvoy’s first NHL action came when he was thrust into the Bruins’ first-round series against the Ottawa Senators in the 2017 playoffs. He made an impression that began his development into a top-pair defenseman.

This season, at just 21, he’s embarking on his third Stanley Cup Playoffs, and he’s doing it for the first time with some momentum.

“I think his first playoffs, he hit the ground running,” Bruins head coach Bruce Cassidy said. “Bright-eyed kid, didn’t know what to expect, and off he went. Last year, excited it’s his second playoffs and because he missed time, the pace, there was a little bit of rust.

“This year I think he’s really been playing at a high level the last six weeks. I expect he will continue that.... He got a taste of it last year, I expect he’ll be a real good player for us.”

With Kevan Miller out for the foreseeable future and John Moore still sidelined, McAvoy has even more responsibility on the blue line.

Toss in the lack of experience for Steven Kampfer and Connor Clifton, one of whom will be thrust into action on Thursday for Game 1, and it’s McAvoy’s time to be a leader.

“We’re going to need him,” Cassidy said. “Kevan won’t start with us, (Brandon) Carlo’s first playoffs. I expect Carlo will have some nerves, it’s his first playoff. ... Clifton, if he’s in, or Kampfer, they haven’t played a ton for us, so Charlie’s going to be really relied on. He is anyways, but a little more than usual early on. He’s going to need to be at his peak, and as far as I can tell, he’s ready.”

Speed kills

The Bruins are focused on adapting to the fast-paced style the Maple Leafs like to play, which means adjusting the lineup accordingly. It already appears Karson Kuhlman will play in lieu of David Backes. The B’s are doing all they can to make sure they are prepared.

“I think we’re going to dress our fastest lineup (for Game 1),” Cassidy said. “I just think that’s how the series is going to start out.”

Familiarity also helps the Bruins in this series, even though they faced Toronto just once after the calendar turned to 2019.

“I think any time they’re in the same division and you play them so many times and you saw them in the playoffs last season as well, that you’re more familiar,” winger Jake DeBrusk said. “You understand you could possibly play them in the playoffs and make sure to play hard. I think that’s what the playoff series are all about with adjustments and elements in that aspect. They do play a hard system and play hard, especially up front and like to transition fast, so we have to be ready for that.”