Why would Tannenbaum take a step down from President of football operations to GM. Makes no sense.
He doesn't have to "step down" to the title of GM. He can be the VP and the GM, or hire someone else to be the GM. Or just be the VP and run ****.
Point is, he has the power to do whatever he wants.
New England for example doesn't have a GM, technically, but Bill Belichek runs player personnel. People say he is the coach and the "GM" because of what he does, but I don't believe he necessarily has the title.