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.
To say that Watt had a successful 2012 season is an understatement. Watt destroyed the competition last year, topping 80 tackles, posting 20.5 sacks and finishing the season as the top overall IDP. If there's a downside with Watt in 2013, it's that he carries with him a very hefty asking price, one that may be hard to justify unless he backs up last season's gaudy production.