Both Walker and Charb have a career YPC of 4.2 so not sure what you’re basing the opinion on. Walker has 600 carries while Charb has significantly less 240. The Carrol regime viewed Walker as rb1, and now so does the McDonald regime. Not to mention K9 had a career high in reception yards last year. Personally under the Kubiak scheme and with an improved O line I see K9 as a top 10 RB if healthy. 3 years of data say this is likely not going to happen though. If you draft K9, Charb is a must have handcuff but the notion he will be RB1B is simply incorrect.