"We can and we will," Dubas said.
Nylander, 22, is a restricted free agent. He was third on the Maple Leafs with 61 points (20 goals, 41 assists) in 82 games last season, and had four points (one goal, three assists) in seven games against the Boston Bruins in the Eastern Conference First Round.
RELATED: [Behind the Numbers: Tavares gives Maple Leafs center combination similar to Penguins']
Marner, 21, led Toronto with 69 points (22 goals, 47 assists). Matthews, 20, was second with 63 points in 62 games, and his 34 goals were second to James van Riemsdyk's 36. Marner and Matthews became eligible for contract extensions July 1 and can become restricted free agents after the 2018-19 season.
Dubas said he there wasn't any order he wanted to get the contracts done.
"I think the easy answer is there's only one of them that doesn't have a contract for next season and that's William," he said. "These are all very important players to the Maple Leafs and to our future. Rather than rushing to get them done on the first day, if a player is going to be signing up here long term … you need to sit with them and convey to them what the vision for the team is and what they're signing up for, for the next however many years it is."