From TV Guide:
B.J. Novak, who has doubled as a writer off-screen and a series regular on-screen since The Office’s 2005 launch, is leaving as a full-time part of the show.
Novak will remain a member of the extended Office family, however. Even though he no longer has a deal in place with series producer Universal TV, Novak is expected to make recurring appearances on The Office and could even still do some writing for the show.
… executive producer Greg Daniels… is returning full time to oversee the show’s creative evolution this season.
Link: B.J. Novak Takes an Office Breather