According to Elliotte Friedman of Sportsnet, Giordano, 31, will earn $6.75 million per year amid the reported $40.5 million deal.
The defenseman has served as Calgary's captain since 2013.
Giordano was an All-Star last season and had 11 goals and 37 assists in 61 games before experiencing a biceps injury that sidelined him for the last 21 regular season games and playoffs.
The Toronto-native has 66 goals and 179 assists in his nine NHL seasons, all with Calgary.
Giordano signed with the Flames as an undrafted free agent in 2004.
- Kayla Lombardo