He turned down Sunderland after meeting with Martin Bain and Walter Smith, and my belief is he was given the heads up from Smith at Pedro was going to get dunted at Rangers, sit tight and that job is yours,
The move to rangers was supposed to be a straight forward, McInnes resigns and moves,
The two issues were that McInnes refused to resign forcing rangers to pay compensation , and the rangers board were shocked when they heard the salary that McInnes had got out of Milne.
Also rumours that Rangers weren't wanting Docherty as the assistant due to his green and white leanings