Brent Burns made the medal stand, but he did not pick up his second career Norris Trophy on Wednesday.
Burns, 34, scored 83 points (16 goals, 67 assists) in 82 games, setting a Sharks franchise record for points by a defenseman. He became the first blueliner to score at least 82 points in a season since Karlsson did so with the Ottawa Senators in 2015-16, and only the 48th in NHL history.
This marked the third time in the last four seasons that Burns was a finalist for the award, and he dressed for the occasion.
Burns finished second in the Professional Hockey Writers Association's balloting.
Giordano, 35, scored a career-high 74 points (17 goals, 57 assists) and led the Western Conference-leading Flames in ice time en route to being a first-time Norris finalist.
Tampa Bay Lightning defenseman Victor Hedman was the other nominee. Hedman, 28, scored 54 points (12 goals, 42 assists) in 70 games, leading the loaded Lightning to a runaway President's Trophy win in a record-setting regular season.