I would definitely go with A. Foster and P. Thomas. They have both become integral parts of their offenses and I believe will receive a significant amount more carries than your other two options. C. Benson has not looked great and A. Bradshaw may still lose carries to B. Jacobs.
Hmm....I may be a little contrarian here, so I will explain my answer. I definitely start Benson against Carolina. Carolina is starting Clausen (a rook), which should lead to ints, which should lead to a short field, which will likely lead to tds a plenty. Also a big lead means Benson gets more carries. Look for him to bounce back here.
The other choice is tougher, I will admit. It is difficult to bench Foster as he is producing quite well. But, Dallas' run defense has been really stiff so far. Maybe that is a direct result of who they have played (Was, Chi), but maybe they are that tough. Keep in mind Foster will also be without his starting LT.
PT faces Atlanta who has been fairly generous to the running game, but a lot of those yards came off of big plays (Mendenhall in OT and Hightower on a long scamper). While the yards average doesn't look good, they have been a little stiffer than the stats show.
As for Bradshaw, he is going against Ten, who is stiff against the pass, but not as much against the run.
It looks like based upon your post it is a PPR league (or some semblence thereof) so I would go with PT as he will get the lions share of carries and with Bush out he also gets most of the receptions. Good luck.
Thank you for helping me with my desision standard league flex RB/WR option QB Mat Schaub RB Adrian Peterson, Lesean McCoy, Ronnie Brown (flex) WR Reggie Wayne, Percy Harvin Def. Dallas Bench: QB Kevin Kolb, Michael Vick RB Justin Forsett, Laurence Moureny WR Kris Chambers, Mark Clayton Vincent Jackson
I like betacheers logic with Benson. Was going to say Thomas and Bradshaw but now thinking Thomas and Benson are your guys. With Bush out, PT will get most all the work. I think they signed Betts again but Ivory has yet to get healthy. I have Foster in one league and, though hard to do, am sitting him in favor of Tolbert as Cowboy D held Portis and Forte in check. Good luck this week!
QB - Drew Brees RB - Arian Foster, Ryan Mathews, Trent Richardson, Stevan Ridley, Mikel Leshoure WR - Julio Jones, A J Green, Dez Bryant, Demaryius Thomas, Kenny Britt TE - Jimmy Graham K - Blair Walsh D/ST - Texans