OTTAWA -- Brady Tkachuk is losing more than just a teammate and former landlord in Mark Stone.

The rookie forward is also saying goodbye to an embraced mentor in the Ottawa Senators dressing room.

Stone and his girlfriend, Hayley Thompson, invited Tkachuk, selected No. 4 by the Senators in the 2018 NHL Draft, to live with them at their Ottawa home at the beginning of the season.

Now the 19-year-old must take on more responsibility after Stone was traded to the Vegas Golden Knights with forward Tobias Lindberg for forward Oscar Lindberg, defenseman prospect Erik Brannstrom and a second-round pick in the 2020 NHL Draft.

"He had a huge impact for me this year both on and off the ice," Tkachuk said after Senators practice on Monday. "I got to be close to him … it was an honor to play with him."

Tkachuk, who moved into his own apartment recently, said Stone's guidance is something he'll never forget.

"He welcomed me into his home when he didn't have to," Tkachuk said. "He took me under his wing. It means so much to me. He didn't have to. That's the type of person he is. For this team he was our leader. He brought it every day. He works hard all the time.

"What did I learn from him? How he handles himself. I think he's one of the best players in the NHL. He takes care of his body off the ice. On the ice I don't think he's ever had a bad game. He brings it every day and he does anything he can to win. He's just a great guy to have on the team."

Video: CGY@OTT: Tkachuk beats Rittich on breakaway

Former NHLer Keith Tkachuk was in Ottawa to see his two sons, Brady and Calgary Flames forward Matthew, play against each other for the first time on Sunday. During an appearance on the pre-game show on TSN-1200, Keith explained why it was so important to him that the Senators somehow re-sign Stone.

"I want that Mark Stone signed so badly," Keith said. "He's been so instrumental to Brady's development both on and off the ice. The Senators have to figure out a way and get this done."

In the end, they couldn't.

The departure of the 26-year-old forward who has scored 20 or more goals five straight seasons, including an NHL career-high 28 this season, made an inexperienced Senators team even younger. Ottawa had nine players age 22 and under in their lineup during a 3-0 loss to the Columbus Blue Jackets at Canadian Tire Center on Friday.

With the Senators all-in on their rebuild, the future lies in a youthful talented core led by Tkachuk and 22-year-old defenseman Thomas Chabot.

Tkachuk is fifth in NHL rookie scoring with 31 points (14 goals, 17 assists), one behind teammate Colin White (13 goals, 19 assists). The recent trades of forwards Matt Duchene, Ryan Dzingel and Stone, meanwhile, means Chabot becomes the leading scorer on the Senators with 47 points (13 goals, 34 assists).

"Guys leave; that's the business of hockey," Chabot said. "I mean, I learned so much from Erik Karlsson last year. He was so great to me. But if he had not gotten traded (to the San Jose Sharks) this season, I would not be getting the same type of ice time or opportunities that I am."

Make no mistake. This is Brady Tkachuk and Thomas Chabot's team now, inexperienced as they might be.

Video: OTT@CHI: Chabot roofs one from a tight angle