There's no short answer here.
In reps during warm-ups TJ has been seen on a few times right behind EL. That said, allow me to ramble for a second...
We've always had a little laugh on Saban and depth charts. Any Bama fan that follows the team closely knows his propensity for using the term organizational groupings.
In some cases, we could have a legit depth chart: the offensive line for example. In other cases the groupings term fits. Take the linebackers. In our discussions here about returning starters we have seen how we have guys returning that have had six and seven starts last season because there were games where we started in a nickel or dime set. If you looked at the base set you wouldn't call CJ a starter, but the fact is he started a lot last year.
In my view the same can be said for our running backs this year.
I haven't thought a lot about who is #2 on the depth chart but I have thought about who might end up #2 in total rushing yards at the end of the season. I've also wondered if we'll see one guy that ends up #2 in rushing yards and another in total yards.
Hell, just this week we have Saban talking about using Drake this season giving us Drake, Fowler, Lacy, Hart, and Yeldon.
So, in answering your question I'd say for TV broadcast purposes we'll call Yeldon #2; today. Sept. 2nd we'll probably have one back leading in carries, one (perhaps the same guy) in yards gained, another leading in total yards, one in receiving yards out of the backfield...

anic:
Bottom line:
Here's what important.
Hart wears #1.
Lacy #42.
Fowler #45.
Yeldon #4.
And Drake #17.
Learn those numbers...that way you'll at least know who is on the field.
Then there's #6...