Australian paceman Mitchell Johnson has been ruled out of the fourth Test with India at the SCG after failing to prove his fitness with a hamstring injury. Australian team physio Alex Kountouris was quoted on the Cricket Australia website on Sunday morning saying Johnson was out of the final Test of the series, in which Australia holds an unassailable 2-0 lead. His absence in Sydney opens the door for Mitchell Starc or Peter Siddle to replace him in Australia's XI.