Following Jon Murphy on Twitter (@JonMurphy_PES) has many benefits (do it now if you aren't already doing so!!). He responds to every question from fans all over the world, and keeps everyone up to date with what's going on with PES.
He was recently asked whether there would be updates to the rosters, that would take the missing summer transfers into consideration.
Jon responded, and confirmed:
"DLC to update rosters and add content - expected around two weeks after launch. Date still TBC".
So we'll only be waiting a fortnight or so, for Zlatan to finally make his move to Milan. Good job, Konami!