Strength of schedule is calculated from the opponents projected fantasy points allowed for the RB position. The best rating is +16 which gives the player the advantage against the defense and indicates an easy opponent, the worst rating is -16 which gives the defense the advantage and indicates a tough opponent.
Edge gets new life in Seattle but the offense isn't all that great to start with and Edge isn't as quick as he used to be. He'll get some touches but not enough to warrant a selection. Late round flyer at best.