The problem with Stewart is that he's on Detroit. Detroit sucks, and will be playing from behind most of the year, which means Stewart doesn't get many carries.
Are you referring to Jamel White? He'd be okay, but you never know when W. Green will become the starter in CLE. Same thing with Duckett, Dunn has looked very good so far, so Duckett will come in for spot carries only and if ATL is within the three yard line.
Shanahan will continue to do the RBBC approach, so Portis might not get a fair shake unless O. Gary goes down with an injury.
Bennett is going to have better numbers this week. I'd play him.
I was really surprised to see M. Robinson only get one catch while Booker had nearly ten. I guess they're trying to justify that fat contract they gave him. Personally, I think opposing defenses don't respect Booker enough and they'll keep throwing to him until teams get the hint. Then they'll throw more to M. Robinson and Dez White and David Terrell. For now, keep M. Robinson as a bye-week plugin unless you need another starter, then try to trade him.
Why wouldn't you consider playing a WR for the WR/RB position? Are you weak at WR?
Finally, the Chargers will never move to LA...