Week 8 Bye

I’m sitting at 3-0 for a league in which I own Todd Gurley and Ty Montgomery.
They both have a week 8 bye which is why my initial plan was to sell Gurley high after this week but would it be better to keep both and try picking up/trading for a replacement?
I also have Doug Martin awaiting his 2017 debut in my bench and Tarik Cohen that I snagged off of the waivers.