It’s always the same. We take the starter for granted even though he is used for the tough yards. After the starter spends a couple of drives wearing out the defense, in skips the smaller but flashier backup to take advantage of the starter’s hard work.
The backup RB knifes through the fatigued defense and everyone forgets that he was resting comfortably during the first ten minutes of the game. Interestingly, he spends half the time on the field that the starter did but now he returns to the bench and waits until he is fully rested before returning to the field.
RB’s like Marion Barber, Joseph Randle, and Tony Pollard are the beneficiaries of the starters effect on the opponent defense but whenever it was time for them to carry the larger load, their contributions do not make the proportional jump. Quite often, they end up on injured reserve.
Pollard should not be the starter, he would be far more effective in his present role., No disrespect intended, he's not built to take the beating that Zeke is constantly subjected to, both he and his productivity would not last half a season. I would be willing to make him the starter and reverse the number of carries for a few games just to demonstrate my point.