Here is a brief excerpt from the report over at
Deadline.
Zach Galifianakis is withdrawing from starring with Ryan Reynolds in the Universal Pictures supernatural comedy R.I.P.D., which Robert Schwentke will direct. Galifianakis liked the project just fine--it's about a force of undead police officers based on the Peter Lenkov comic--but scheduling just got too hairy...But there was no certainty whether those plans would fit in because Warner Bros has an option on Reynolds, who might be obliged to do a sequel to Green Lantern quickly.
Stay tuned for more updates and details on the movie (possibly set to be released either in 2012 or 2013) as we have them!