It seems like he isn't getting along with Dan Harmon at all, and he doesn't even think the show is good.
http://www.radaronline.com/exclusives/2012/04/chevy-chase-attack-show-dan-harmon-community-voicemail
Sounds like he may not be back for season 4!
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The batman villians all seem to be one big joke that batman refuses to laugh at - SantaRPG