Stacy played less because St. Louis was down so much and Cunningham is a better pass catcher. Granted, St. Louis might be down often this season. I'm not sold on the Rams being one of the 5 worst teams in the NFL just yet, but they very well may be. 5 worst offenses though? Probably.
I'd go Bell and Mathews, but Stacy vs Mathews is really close given the matchup.