Make a Trade or Stand Pat?

I am in a 12-team PPR league with a short bench. We have no flex and can only start 2 RBs. I have Gurley, Mixon, Kerryon, and Chubb. I am thinking about stashing Malcolm Brown, just in case. However, I simply can’t roster 5 RBs. My team is doing very well, and part of me just thinks I should leave it alone and ride it out. If I did trade an RB (not Gurley), I would target a WR 2. I start 3 wide receivers and have Thielen, JuJu, Edelman, Funchess and Sanu.

What do you think? Should I go ahead and trade a RB to pick up Malcolm Brown or maybe even drop Sanu and have 5 RBs?