In Detroits defense, I don't believe Anderson can play off the ball full time as a linebacker, I don't believe he can set the edge to the extent that they demand of their defensive ends. That makes him a situational guy that you move around, an excellent one, but I dont think that provides enough value at 6.
regarding Carter, it isnt just poor character the lions try to avoid. They want gym rats who love and are passionate about football, live and breathe it. That doesn't seem to be Carter.