Few NHL clubs are ever completely satisfied with the state of their blue line. Well, outside of Nashville, that is. And, as such, most teams head into summer looking to either address major issues on the back end or at least add some defensive depth. The Calgary Flames aren’t immune to this, but they at least fall into that second group. They need some help on defense, but it’s more of a depth concern than anything else. The core is in place for the foreseeable future, with Mark Giordano, Dougie Hamilton and T.J. Brodie all locked in for at least the next three years. Beyond that though, Matt Bartkowski is the only other blueliner signed for next season. That means Michael Stone, Dennis Wideman and Deryk Engelland are all set to become unrestricted free agents this summer. And while the Flames might bring back a guy like Stone, they’d likely want a reduced price from the $4 million he got from Arizona last summer. And they’re going to look outside the organization as well. With Giordano, Hamilton and Brodie, Calgary has an impressive top three. So while they’ll need to add a couple of pieces to completely round out the defense corps, the main focus will be on bringing in a solid No. 4. If they can do that, those top two pairings will be pretty formidable. Naming that fourth defenseman will take some time though. Giordano and Hamilton typically make up the top pair, so whoever they add will be brought in with the intention of lining him up alongside Brodie. Since Brodie is a left-handed shot, Calgary’s preference would probably be to land a right-hander. Of course, the top name among blueliners on all free agent boards this summer will be Kevin Shattenkirk. And while he is a righty, he’s also far too expensive for a team that already has over $17 million per year tied up in its top three defensemen. Cody Franson could potentially be a more realistic choice though.