It seems like Metal Gear Solid: Rising is not being developed by Kojima Productions, instead it is being developed by Platinum Games, developers of Bayonetta. By bringing in a new developer, the game itself has changed from Hideo Kojima's original plan.
Originally, Kojima wanted Rising to take place before Metal Gear Solid 4 in order to show what happened to Raiden, but Platinum Games changed all of that. In order to give the new developer more creating room for their own story, the setting has been changed from before the fourth game to years after it.
Just because a new developer is doing their own thing it doesn't mean Kojima Productions isn't involved. Kojima's team is watching over the Metal Gear Solid: Rising developers, making sure things are going according to the series writing.
Also, according to Konami, more Metal Gear Solid: Rising announcements will take place this Tuesday on their website.
