Who do i start week 4?

I think I would start Buffalo over Dallas. Dallas' defense is good but they are playing Washington in a huge rivalry. Buffalo is playing St. Louis who has looked completely inefficient on offense so far this season. Washington has the 17th rated offense and St. Louis is second to last only ahead of the Browns. Buffalo has the 5th ranked defense and Dallas has the 9th. If it were my team I would make that switch.