To me, this sounds like a cop who goes berzerk and guns down three little old ladies and then takes himself to the Chief of Police and and says: "Chief, I've decided to place myself on administrative leave until all the facts are in."
I'm really not sure it works this way.
I'm pretty sure that Brian Williams was told that he would not be on the air for a few days. Which is to say -- I think Brian Williams is lying about why he won't be on the air for a few days.