Messi apparently didn't like at a all the communication of the board: they promised Neymar, when they knew it was just bluf... And had allready took Griezman.
Whatever I think if Messi goes to the clash it is because he knows (and hi advocate of course),he has an open gate... I guess he will go to Man City (or join his friend Neymar in PSG ? depends also on finacial fair play). It's true that the adaptation of an old Messi to the physical football in england is questionable.