As far as I can see, Murdoch has offered some advice to Tony Abbott in an informal and highly public manner...
Tony Abbott may or may not take this publicly offered advice in much the same way as he might find value in a opinion someone expresses in letters to the editor or in a published opinion piece...
I would imagine that Murdoch has pretty good sources of information and it is quite possible that this move is in planning in any case and Murdoch is just offering his advice publicly that it is a good idea to get a PA with a more specialized skill set and experience...
