Prop Up Meaning

(transitive, idiomatic) To be at the bottom of (a league)

Example: 2014, Jamie Jackson, "Fans' revolt leaves David Moyes dead man walking at Manchester United", The Guardian, 26 March 2014:
  Under Moyes, United have fewer home points (21) than Norwich City and Hull City, with their count of 18 goals the same as Fulham and Cardiff City, who prop up the table.