Not really. He never picked himself as captain did he? His rapid and sudden decline started when the story about him wanting to go back home emerged. He wasn't himself prior to that, but he wasn't the complete train wreck he is now. Having said that, if he had been turning in these performances in a team that functioned with a purpose and direction, and Colo had been the weak link, I'd agree totally. No one out there, apart from Krul probably, has a clue what they are supposed to be doing. No one!
EDIT: I totally agree regarding the captaincy issue that he should lead from the front, but it's clearly not his thing. Pardew should recognize this and take it off him and hand it to someone who understands the responsibility that comes with it!
Oh right. None of the players 'pick' their responsibilities so we can just absolve them all.