TORONTO — Nazem Kadri's time with the Maple Leafs is over.

Tyson Barrie's has just begun on what is all of a sudden a new-look Toronto blue line.

The Leafs swung a big trade Monday night to cap a frenzied first day of NHL free agency, shipping Kadri, defenceman Calle Rosen and a third-round selection in the 2020 NHL draft to Colorado for Barrie, forward Alex Kerfoot and a sixth-rounder next June.

The Avalanche will also pick up 50 per cent of the remaining US$5.5 million owed to Barrie, who is set to become an unrestricted free agent next summer and is the key to the deal for Toronto as a right-shot option on the back end.

"We've talked to Colorado on and off for a while and then picked things up the last couple of days," Dubas said on a conference call. "It's just a mutual fit there — they're interested in Naz and our ambition (was) to improve our defence."

The trade was one of two made by the Leafs in less than 12 hours after Toronto started Monday by sending the wantaway Nikita Zaitsev to the Ottawa Senators in a six-player swap that included fellow blue-liners Cody Ceci and Ben Harpur going the other way. The Senators also signed veteran defenceman Ron Hainsey, who spent the last two seasons with the Leafs, winger Tyler Ennis, and got forward Connor Brown in the Zaitsev trade.

With Jake Gardiner a UFA and the Leafs saving salary cap space to sign star restricted free agent winger Mitch Marner, it's possible Toronto will have just one defenceman — Morgan Rielly — on its opening night roster from the group that was together in January 2018.

"A lot of it was circumstantial," Dubas said of the blue-line turnover. "We owe it to our forward group and (Frederik) Andersen in net to round it out as best we can and put the best team we possibly can on the ice, particularly defencemen that can move the puck effectively and efficiently.

"I think we've accomplished that today and we're real excited to see it in action come the fall."

Jake Muzzin, who Toronto acquired in January from the Los Angeles Kings, Ceci and Barrie are all pending UFAs next summer, but Dubas said that's not a major concern. He'll eventually have contract discussions with all three and pointed to a decent stable of youngsters, including Travis Dermott, who will miss the start of the season after undergoing shoulder surgery, as well as Rasmus Sandin and Timothy Liljegren in the American Hockey League.

"We've got good depth," Dubas said. "We'll see how it all plays out."

Kadri's final act with the Leafs came in a seven-game loss to Boston in the opening round of the playoffs — the second in as many years — when he delivered a cross-check to the head of Bruins forward Jake DeBrusk. Kadri was suspended for the rest of the series, which turned out to be five games, after receiving a three-game ban for a similar incident the previous spring against Boston.

Dubas was asked after the season if he could trust Kadri to not lose his cool in critical moments moving forward, but he said Monday that didn't play into the trade discussion. The 28-year-old, who had back-to-back 30-goal seasons in 2016-17 and 2017-18, also has a palatable salary cap hit of US$4.5 million for the next three seasons.

"Teams look at our roster and are looking for centres and know we're very fortunate with Auston (Matthews) and John (Tavares) ... (it) pushed Naz down into that third slot," said the GM. "Teams look at that and maybe saw somebody there that they could acquire to fill a need higher in the lineup."

Dubas, who also signed veteran centre Jason Spezza at the league minimum of $700,000 on Monday, said he isn't concerned about losing the toughness Kadri brought to a lineup that could be lacking on the physical side up front.

"I would love us to be the most skilled and the biggest and the grittiest team going, but talent will come first," he said. "I think as time evolves and our guys continue to grow, they'll develop their own sense of grit."

The "offensive-minded" Barrie dressed in 78 games for the Avalanche in 2018-19, registering 14 goals and 59 points.

"I was surprised, it kind of came out of nowhere," the 27-year-old said of the trade. "(But) I can't wait to get there and try and win a Stanley Cup with these guys."

In 484 career regular-season games, all with Colorado, the Victoria native drafted in the third round back in 2009 has produced 75 goals and 307 points.

"I'm coming into my prime," Barrie added. "The last half of the year and playoffs, I was playing some really good hockey."

Kerfoot, 24, appeared in 78 games for the Avalanche in 2018-19 and recorded 15 goals and 42 points.

The Vancouver product was originally selected by New Jersey in the fifth round in 2012, but instead chose to sign an entry-level contract with Colorado as a free agent in August 2017.

Kadri had spent his entire career with Toronto after being selected seventh overall in 2009, putting up 161 goals and 357 points in 561 regular-season games.

"Nazem is a proven goal scorer and a fierce competitor who plays in all situations," Avalanche general manager Joe Sakic said in a statement. "He is under contract for the next three seasons and will immediately fit right in as our second-line centre and improve our scoring depth.

"With the arrival and emergence of (young defencemen) Samuel Girard and Cale Makar, as well as the recent draft pick of Bowen Byram, we felt it was time to move in this direction with Tyson's contract expiring next summer."

-With files from Kyle Cicerella

___

Follow @JClipperton_CP on Twitter

Joshua Clipperton, The Canadian Press