Strength of schedule is calculated from the opponents projected fantasy points allowed for the WR 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.
Our projections of 25/300/2 would all be career highs for Harris. So as you can see, there isn’t much history to go on here. He does play behind the injury-prone Miles Austin so he does merit keeping an eye on.