I think Matthews has been too inconsistent to play, especially with Tolbert getting the goal line work. In my opinion, it's easy. MJD and Torain, no doubt.
Gotta say for me its Matthews and Torain. Matthews for the reasons you listed. Torain is coming off of a good week running, with Portis out, he is going to get the touches and if the Seahawks can get decent rushing numbers against Chicago, I have to believe in the Skins run game. Tough D for sure, but I still think there is a good chance of production here. MJD hasn't been "on" this season, and I think the QB situation hurts more than helps, they will know MJD is the dangerous weapon and will probably be the number one concern for the defense. Hope this helps, and good luck.
QB - A Rodgers, E Manning RB - A Foster, S Jackson, R Mendenhall, T Jones, R Bush WR - G Jennings, L Fitz, S Smith (Car), P Harvin, V Jackson TE - A Hernandez, J Tamme