According to a report from Boston Bruins insider Joe Haggerty, the team is targeting free agent defenseman Karl Alzner as a potential fit for some veteran depth on the blue line.
From Haggerty's most recent column from Boston Hockey Now:
One of those possibilities, according to a couple of hockey sources, is free agent defenseman Karl Alzner, who has played just 13 NHL games over the last two seasons while buried in the minors with an unwieldy contract. His forgettable stint with the Canadiens ended when he was bought out of the final two years of a five-year, $23 million contract following last season.
The 32-year-old has now been freed of that albatross deal weighing down his career, and would make a cheap insurance veteran insurance policy as a left-handed D possibility should youngsters like Vaakanainen and Zboril show they aren’t quite ready for prime time.
As Haggerty mentions, Alzner has played just 13 NHL games over the past two seasons but that had more to do with his contract than it does his actual quality of play. The 6 foot, 2 inch, 210 pound Alzner was a reliable defensive defenceman for the Washington Capitals for years and there's reason to believe that he can be a depth contributor on the Bruins' blueline.
Alzner would likely come very cheap, maybe even at league minimum, and can provide the Bruins' with some insurance if youngsters like Urho Vaakanainen and Jakub Zboril prove unfit for full-time minutes at the start of the season.