Not excusing it as he is a pro keeper but you have to wonder if playing at a 'big' stadium in front of a crowd has such a negative effect on these guys. We saw it with Kovar last season and this guy seemed to be a huge bag of nerves. I know in the Under 23s they play in front of a handful of colleagues so could the fact 2,500 fans are there cause these guys to turn to shit?
I imagine the mental pressure of fans is very different, but I also think a big change is the way the game is played. It's quicker, more balls into the box, less control etc. I think Goalkeepers see more of the ball and in different situations to how it works in U23 football and below. I'd imagine, but have no data to back this claim up, that more Keepers progress up the leagues than other positions, and more who have been on loan do well than other positions. In the long term.