Good call thinking about this now, there’s a good chance if the Rams lock in a #1 seed Gurley won’t be seeing much of the field come week 17.
Though he didn’t play all season, based on how well he performed in the preseason (3 games played, 46 att. [15.3 att/g] 197yds, 3 td, 6 targets, 6rec), John Kelly proved he can play. Justin Davis hasn’t suited up all season either, but he also only played in 1 preseason game, where he had 7att. for 41 yds and 0 td.
Though Justin Davis has a full year under his belt with the team, I personally feel Kelly will be the one with the more significant PPR fantasy impact in the event Gurley goes down or is benched.
I would keep my eye out this weekend to see who the Rams utilize more with Brown out of the equation, but if I had to make my decision right now, I would say Kelly is the more clear-cut backup to Gurley.
Best of luck!