I don't see it, not only are the articles on the major sites very poorly written, it would go against what Notch has said about things like Facebook/Occulus.
If MS do do it, then for me it's a total waste of cash, they would be better off buying Take2, which has tons of very important IP... though after what they did to their PC division I wouldn't hold out hope for how they would handle it.
Buying Minecraft, well it's a cash cow thats for certain, but whats the point, the game is available on PS4/PS3 right now, they could cancel it, but whats the point, its already in the wild/distributed etc. So they would have to make a Minecraft 2 to be more successful, and one thing is for certain, just cause it's making money today, doesn't mean it will make money tomorrow.... as Runescape will attest to.
Personally I don't believe it.