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.
In what may turn out to be a blessing in disguise, Jones was released by the Raiders the day after the draft. It was clear that Jones wasn't going to be a big part of the Raiders offense in 2015 so this will now give him a chance to catch on with a wide receiver-needy team. But remember to draft with caution, as Jones is on the downside of a mediocre career.