The reason is depth. Josh Jacobs, was mostly the third back in through his 3 years at Bama and yet was the number one running back taken in the draft. Brian has played with Jacobs, Najee Harris, Damien Harris, Bo Scarbrough, and the guys who are now behind him.
I'm not saying anything about the score. I'm telling you what you are very likely going to see Saturday, at least the pecking order as it stands now. I've listened to the guys you are counting on, I don't find anything anyone has said necessarily offensive. It's more informative, regardless of how the game turns out.