As far as I understand it, because I was at an information meeting which the City of Toronto put forth, they said that they were willing to transfer all of the lands owned by the City of Toronto, except, of course, the zoo. The zoo is a separate entity and the zoo lands are not being included, but the valley lands that are not owned by the zoo are not being included. Neither is the Morningside tributary.
On October 27th, 2014. See this statement in context.