Not sure he wouldve dropped down the pecking order, but maybe they wanted that work horse slog it out pace bowler over in Pakistan rather than an express bowler who might be better suited to short stints.
I have heard that Pakistan are preparing their pitches to be quicker and more pace friendly... most likely due to Shaheen, but also to help them when they travel overseas.
Will be interesting if they serve up a pacey pitch against the Aussies though... I'd imagine we're heading over there expecting spin friendly decks and therefore no point running Jhye into the ground