I don't know if it's a rough patch, more like Campbell isn't making crucial saves on prime scoring opportunities like he was in the past bailing out the Leafs and allowing the offence to win games. When Campbell was dominating he would always have a handful of monster saves early in games and then throughout allowing the Leafs offence to take over.
I don't know the statistics and am not concerned, all I can see with my eyes is a defence corps with no star player, no #1 defenceman, marginal physicality, and two very young defenceman getting more and more icetime. We cannot assume Campbell will continue to put up vezina numbers in order to win. Team still just isn't good enough defensively and this will be further exposed come playoff time.