Turris, whose five-year, $17.5 million contract expires after this season, signed a six-year, $36 million contract that will keep him with Nashville through the 2022-23 season.
Duchene, 26, had 10 points (four goals, six assists) in 14 games with Colorado this season, including a goal and an assist in a 5-4 shootout win at the Philadelphia Flyers. He had 41 points (18 goals, 23 assists) and was minus-34 in 77 games last season, when Colorado finished last in the NHL with 48 points (22-56-4).
Duchene said he had an idea he was traded before he was pulled from the game Sunday.
"I saw them talking on the bench," he said. "It was very strange, but I half-expected it to be the weirdest way possible. It's one of those things, it's a business and I'll have a good story for people one day."
Duchene also said he's relieved because he has been the subject of trade rumors going back to last season. His contract runs through the 2018-19 season and has an average annual value of $6 million.