Chevy Chase is graduating from Community earlier than expected. THR reports that Chase will be leaving the show effective immediately after starring as Pierce Hawthorne for more-than three seasons. The fourth season is almost done filming, with only one or two more episodes yet to be produced. At this time it is not known if Chase's departure will be written into the show, but it is not expected to impact production. Chase will also still appear in the season finale.
Chase and NBC have had a tumultuous relationship since Chase grew fustrated with the direction his character was going. This is just the latest in a bunch of detours the show has had to face during it's fourth season. The show was only renewed at the last minute this May, and was originally slotted for Friday.
NBC pushed the shows return to October 19th in an effort to properly promote it, but then moved it back to Thursdays at 8 pm. The fourth will now officially air on February 7, and fans will hopefully not lose any further cast members.