Strength of schedule is calculated from the opponents projected fantasy points allowed for the DL 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.
Terrell Suggs' Achilles got all the publicity, but defensive tackle Haloti Ngata also had a down year due to injury for the Baltimore Ravens last year. The eighth-year veteran battle a balky knee last year that cost him two games and limited him in others, and Ngata's 51 tackles in 2012 was his lowest output since 2009. A healthy Ngata should rebound a bit in 2013, leaving him a low-end IDP DL2 in "standard" IDP leagues but an elite option if your fantasy league requires his position.