Smith, who went 19-26-9 in 55 games last season, his 11th in the NHL, has two years remaining on his contract with an average annual value of $5.67 million.
"He's a young 35. … He's got a low odometer on him, I'd say," Treliving said. "I think the way he looks after his body, there's a little bit of a genetic freak with this guy that I don't think the age is going to be something that we're hopefully concerned with, and we think [with] the term left in his contract, he's going to give us good play.
"He's a driven guy … very, very competitive and he pushes people around him."
Smith should have plenty of support from a group of defensemen that includes captain Mark Giordano, Dougie Hamilton and TJ Brodie. The Flames added Travis Hamonic, acquired in a trade with the New York Islanders on June 24 with a conditional fourth-round 2019 draft pick for Calgary's first- and second-round picks in 2018 and a conditional second-round pick in 2019.
Calgary also signed defenseman Michael Stone to a three-year, $10.5 million contract (average annual value $3.5 million) on June 30, the day before he could have become an unrestricted free agent. The Flames acquired Stone in a trade with the Coyotes on Feb. 20.