Who should I start, Marshawn Lynch vs San Fran or Larry Johnson vs Oakland?

Marshawn has a pretty good match up and has been consistently pretty good to great but the Bills may throw a lot on San Fran (horrible p defense). Larry Johnson has a great match up and the Chiefs will likely run the ball against a bad run defense (won't throw as much against a good p defense) but he hasn't proved himself a #1 RB since his suspension.