I think it might have something to do with Ernie not wanting a player distracted by transfer negotiations in the starting XI (presuming that the rumoured approach is real). The rumours about him going to Malaysia appeared around about the time of the MV game, so if an approach was made it was probably before Monday, negotiations were still ongoing as of Friday and Ernie wanted his XI to be fully focused on the game. Brockie probably was only ever going to come on if we were trailing late.
All due respect that's a daft reason to completely change your formation and not play your only striker, who is on your books at the time to be a striker.
Looks like a Newcastle Jets connection and possibly the intimation that we weren't too keen on him? He does seem a little slow for Ernie's approach and he's probably on a decent pay cheque.