I think it's very obvious sproles, PT, and Ivory are 1-2-3 in no particular order...Ingram 4th...cadet 5th
It's nice that you think that, but the truth of the matter is that you need to look at who's getting carries right now.
Ingram and Ivory are (rightfully so) splitting carries in similar "workhorse" roles. Over the last two weeks, these two have combined to average 20 carries per game (11.5 for Ingram, 8.5 for Ivory). It should be safe to assume that they would stay at 20 per game, with the distribution shifting a little bit.
When Sproles gets back, he will get his share of touches in the passing game and a few carries per game.
Thomas will get his touches in the passing game and with a few carries per game. Again, over the last two weeks, PT has 5.5 carries per game, with a few more touches in the passing game.
So that's essentially 26 carries per game. Last year we averaged 27 carries per game en route to finishing 6th in the league in rushing. In 2009, we averaged 29 carries per game. So if we mix Sproles in for a few carries per game, we'd be back to the sort of balance that we had in 2009 and 2011.