Fresh set of legs
It's been clear that the Rams have gotten tremendous production out of featured RB Kyren Williams. But the alternative to Williams lining up in the Rams offense is to play RB Royce Freeman, a runner with a completely different style of running, and someone who brings a new dimension to the Rams offense.
While that can be a direction that the Rams want to explore, the Rams certainly have had to be pleased with the elusive yet productive style of Kyren Williams in recent weeks. And yet, to rest him has also resulted in the Rams offense stalling more frequently. It's clear that the Rams offense needs to maintain the threat of attacking between the tackles as well as the perimeter
Rivers can run behind this offensive line
While I am not suggesting that RB Ronnie Rivers is a seamless replacement for Kyren Williams, he has his strengths. Next to Williams, he has been the runner up in the Rams offense in terms of yards per carry. In fact, when both Rivers and Williams fell to injury, their production on a per carry basis was very similar.
Now that the Rams have added IOL Kevin Dotson to start at right guard, and expect Rob Havenstein to return as the starter at right tackle, Rivers will have a solid offensive line to run behind in Week 16 if he has the opportunity to carry the football.
Even if just for one offensive series, the presence of Rivers on the Rams roster forces the Saints to study ways to defend him. That added variable to the Rams backfield dilutes the defense's ability to focus exclusively on Kyren Williams, giving the Rams offense a better chance of success.