Maybe a little strong, you rarely see him making mistakes on the defensive side of the puck. If you've noticed that he is good on the PP, it's only because he's one of the better passers on the roster. He's very accurate, and was featured in a In Lou We Trust article for it.
I see no issues with his defensive game. If it wasn't for his defensive game, he'd probably be out of an NHL job by now. My argument is that he has shown nothing more than being a checking center.
Also, I meant "PK" not "PP" (and edited the error in my post).