A wild game of musical chairs is likely to be played out at ABC News within the next three days as Diane Sawyer departs Good Morning America on Friday to take over the anchor desk at ABC World News from the departing Charles Gibson the following Monday. According to various reports, George Stephanopoulos will likely take over Sawyer's role on GMA. Terry Moran, one of the anchors on ABC's Nightline will be handed Stephanopoulos's job on ABC's This Week. Juju Chang will replace Chris Cuomo as news anchor on GMA , while Cuomo would become co-host, with Elizabeth Vargas, of 20-20 , replacing John Stossel, who left the news magazine in October to join Fox News. All that maneuvering would still leave open one seat -- Moran's on Nightline , and a mad scramble is expected to take place to grab it -- with the most likely winner appearing to be either correspondent Jake Tapper or Gwen Ifill, according to several reports.