That happened with a lot of people, because the RB roles hadn't really been established yet. Because up until yesterday, it appeared that Sanders was going to be the featured back, with Howard getting some carries.

But now, it is quite obvious, that Howard is going to be the red zone back and to get the so called tough yards. So Sanders might get you 70 yards or even get 100 yards, but he is not going to get you any touchdowns. Lightening/Thunder 2 back system.