I think KJ is about to break out very soon. It may not be this week against WAS, but after that they face JAX, MIN, IND, ARI, and GB - not exactly premier rush stoppers.
KJ is also obviously becoming the feature back for the Lions - in limited action since he has returned from injury he has looked really good - not only bouncing outside but solid between the tackles as well. Add the fact that he's very good catching out of the backfield, and you almost have to think he's coming close to being a complete tailback (he is an avg blocker - which is great considering where he is in his development).
The Lions biggest weakness on offense right now (aside from keeping WRs healthy) is their run blocking schemes. The Oline is great at pass blocking, but at run blocking they have been unimpressive. As the unit matures along with KJones, they will put up good numbers.
In 3-4 weeks, the Lions offense will be clicking, and it would be smart for us fantasy types to be aware of this before it happens. When healthy, ROY has so far been simply unstoppable (anyone watch him play and disagree?). The defense is obviously coming together too - which will allow the Lions O to open their playbook a bit more than they have been able to. KJ will get roughly 20 touches a game and will be a solid #2 fantasy RB down the homestretch and into the playoffs. Week 13-16 Detroit faces ARI, GB, MIN, CHI. You could do a lot worse.