Is there even a rb worth a 1st in this draft??
There really isn't. Jacobs is considered a top 35 talent, so it wouldn't be a shock to see him go in the first. Henderson has a tremendous skill set to pair with a back like Gurley, but using a first seems like a reach. Sanders has moved up a lot since his combine performance, has elite athleticism, and may profile as the best all around back now.
I still think a trade down makes a ton of sense and a RB could be a top player on their board in that situation. It's not what I would prefer, but if the Rams go RB with their first pick, there must be a reason.
If the Rams need a future RB they are better off waiting until the 2020 draft. There might be 7 or 8 that are better than the ones in this year's draft class