Chevy Chase -- I'm LEAVING 'Community' ... But I Wasn't Fired

Chevy Chase's "Community" college days are OVER ... the actor has struck a deal to leave the NBC sitcom ... effective immediately.

According to The Hollywood Reporter, Chase didn't quit ... nor was he fired ... but it was a "mutual decision" between the actor and producers.

FYI -- producers have already shot the majority of the upcoming season ... and Chase will remain in those episodes. It's unclear if Chase's exit will be explained on the show ... or if it will simply go on as if Pierce Hawthorne never existed.