^^
It's not knee jerking, he's been like this for like a year.Sure he still has fantastic performances, but he's been really inconsistent too. The mistakes he does are also very basic and when they occur they can destroy the entire match. Doing it against Chievo early on in the season may not be a big deal, but come in the CL and he does it against a big club in the Quarters then we are screwed. Juventus aren't a team like Real Madrid or Bayern were we expect to score a whole load of goals each game, we've always been a precise team instead. So letting in a single goal will be more costly for a team like us.
Quite frankly I'm no longer sure which Buffon will turn up, the good or the bad one, so I think he's becoming too much of a risk to have as out number 1 keeper.