In 2018, the LA Rams kept four running backs on the roster: Todd Gurley, Malcolm Brown, Justin Davis, and John Kelly.
In 2019, that number went down to three: Gurley, Brown, and Darrell Henderson.
And for most of 2020, the Rams actually kept five running backs on the roster: Henderson, Brown, Cam Akers, Raymond Calais, and Xavier Jones.
So depending on which iteration of the roster you’re looking at, Sean McVay could potentially choose to keep three, four, or five running backs on LA’s 53-man. Circumstances dictated how many McVay felt he needed in the case of previous seasons and it helps when a team has an MVP candidate at the position with few injury concerns over the period of a few years.