Jarmo Kekalainen has been working the phones trying to beef up the Columbus Blue Jackets' blue line.

The club's general manager made three attempts to acquire a top-flight defenseman so far this summer, but to no avail, reports Aaron Portzline of the Columbus Post-Dispatch.

Shattenkirk remains the only one of the three possibly up for grabs, except his agent said there was no truth to rumors that the Blues are dangling him as trade bait.

Kekalainen told Portzline he will keep sniffing around, but reiterated his belief that a healthy Ryan Murray - the second overall draft pick in 2012 - would be this summer's best acquisition.

As it stands, Fedor Tyutin and Jack Johnson remain the team's highest-paid defensemen, and another high-level player would benefit a team that now boasts quite a solid forward corps and a Vezina Trophy-winning goalie.