Just think about it. His value has gone up drastically since being arguably Sydney's best player of the finals; taking that into account, along with his reputation as a junior, there would be clubs willing to make a Treloar-like offer at this point. It would be absolute madness for Sydney to let him go for one of Hawthorn's late first rounders + steak knives, and that's if they even still have their picks after a possible O'Meara trade. It's not even a matter of principle at this point, Sydney could either let him go for far less than he's worth to both a bitter rival and a flag threat or to another Victorian Club for free and Hawthorn wouldn't get their gun midfielder.
This is one of those scenarios where letting him to to the PSD is better than the trade, assuming he refuses to be traded anywhere else (which I find dubious in this case). Bookmark this post, he will not be a Hawthorn player next year, no chance.
Delude yourself at your will.