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.
He doesn't do anything well but he doesn't do anything poorly either, like most of the people Mangini brought in this offseason he's a max effort guy and should fit in well as a #3. Hopefully Robiskie develops as quickly as expected because he's not a good enough #2 option.