"I think the longer you can have the player for the better," Dubas said. "Coming back from the (All-Star and mandatory five-day) break, I think it makes it a little bit easier than if we were immersed into a full schedule, and it gives Jake a couple days with his family to get organized. Anytime we can allow a player to adapt and give them a little bit more time to adapt versus right at the deadline, when you only have six weeks left, having two plus months for Jake to settle in and help our team was important for us."
Muzzin was selected by the Pittsburgh Penguins in the fifth round (No. 141) of the 2007 NHL Draft. He signed with Los Angeles as a free agent Jan. 4, 2010.
"He's proven himself over a good career now to be able to move the puck, to excel at playing against high quality competition," Dubas said. "He's able to contribute offensively, but defensively, I thought it was a great fit for us and knowing his character and what he's about, I thought it would be a great fit for our locker room as well."
The Kings (20-26-4) are in last place in the Western Conference, eight points behind the Colorado Avalanche for the second Western wild card into the playoffs.
"We're at the bottom of the League. We made this deal for the future of the organization," Los Angeles GM Rob Blake said.
Grundstrom was selected by the Maple Leafs in the second round (No. 57) of the 2016 NHL Draft. The 21-year-old had 29 points (13 goals, 16 assists) in 42 games this season for the Toronto Marlies of the American Hockey League. He will be assigned to Ontario of the AHL.
Toronto selected Durzi in the second round (No. 52) of the 2018 NHL Draft but never signed him. The 20-year-old has 28 points (eight goals, 20 assists) in 24 games for Guelph and Owen Sound in the Ontario Hockey League this season.
It was not easy for the Kings to trade Muzzin, Blake said.
"Terrific player, terrific person. Took a huge step in leadership over the last few years here," Blake said. "... A very difficult day here for us. To move players that have brought so much to this organization and bringing the Stanley Cup to the organization, very difficult, but we wish Jake well. He was tremendous for his time here as an LA King."
NHL.com correspondents Dave McCarthy and Dan Greenspan contributed to this report