The Boston Bruins traded defenceman Brad Stuart and forward Wayne Primeau to the Flames on Saturday for defenceman Andrew Ference and forward Chuck Kobasew.
It's the second big deal made by Flames GM Darryl Sutter in the past two weeks. Calgary acquired centre Craig Conroy from Los Angeles on Jan. 29.
Stuart, a key player in last season's deal that sent former Bruins captain Joe Thornton to San Jose, had been mentioned in recent trade talk because of his upcoming free-agent status.
Boston's inability to work out a new contract with Stuart forced the deal, completed just over an hour after the Bruins beat the New York Islanders 4-3 in a shootout.
"It became evident that when I wasn't having success signing Brad that I was going to have to trade Brad," general manager Peter Chiarelli said.
Stuart, 27, was acquired with Primeau and Marco Sturm on Nov. 30, 2005, for Thornton - who went on to win NHL MVP honours with the Sharks last season.
Boston missed the playoffs and is in danger of doing so again this year. They're last in the Northeast Division with 54 points.
Stuart has seven goals and 10 assists in 47 games this season, but has struggled defensively on the underachieving Bruins with a minus-23 rating.
His best season was with the San Jose Sharks in 2003-04, when he had 36 points and a plus-9 rating.
The six-foot-two, 213-pound native of Rocky Mountain House, Alta., was San Jose's first-round pick, third overall, in the 1998 NHL entry draft.
He has 201 points and 285 penalty minutes with a minus-2 rating over 479 career games with San Jose and Boston.
Stuart joins a talent-rich Calgary blue-line already boasting the likes of Robyn Regehr, Dion Phaneuf and Roman Hamrlik.
Primeau is also an unrestricted free agent at the end of the season. He had seven goals, eight assists and 73 penalty minutes in 50 games for the Bruins this campaign.
Primeau was Buffalo's first round pick, 17th overall, in 1994. The six-foot-four, 231-pound Toronto native never displayed the scoring touch in the NHL that he showed in a promising Ontario Hockey League career with Owen Sound and Oshawa. His best season was also 2003-04, when he had 29 points and 90 penalty minutes in 72 games with the Sharks.
Primeau has 165 points and 676 penalty minutes in 620 career games with Buffalo, Tampa Bay, Pittsburgh, San Jose and Boston.