The mere fact that he's been so reliable in his own zone should be enough to earn him more 5-on-5 icetime, even if he didn't help generate any offense (which he has with 2 assists, I believe). Murphy has been awful in all around, Hamilton, and Harrington have made plenty of mistakes in their own end, as has Wotherspoon.
So, on one hand, you have defenders getting tons of icetime, and responsibilities, who are making mistakes, on the other, you have a severely underutilized defensemen, who has been very reliable in his own end with the limited responsibilities given to him.
Why is Rielly the only one who has to impress in order to earn more icetime? The rest of Canada's blue line certainly hasn't been all that impressive. Actually, Ouellet's been decent, but my point still stands.