Complex sentence: He left the show shortly before Christmas 1976 to undergo surgery for throat cancer, turning the show over to panelist Bill Cullen, with semi-regular panelist Joe Garagiola also having a few weeks to sub-host, claiming he was "pinch-hitting" for Moore.
Split into simpler sentences: He left the show shortly before Christmas 1976 to undergo surgery for throat cancer, turning the show over to panelist Bill Cullen. Semi-regular panelist Joe Garagiola also was given a few weeks to sub-host, claiming he was "pinch-hitting" for Moore.