Strength of schedule is calculated from the opponents projected fantasy points allowed for the DEF 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.
The Packers defense was hit and miss last year, mostly miss. They should improve on their 2008 campaign, but I don't see them as being a fantasy force. A fantasy starting unit? Perhaps, but not one of the top or even second tiers.
Last season, the Packers had some awful luck. they outgained their opponents significantly but couldn't win games. They went 6-10 but 7 of those losses were extremely close, by an average of 3 points if memory serves me.
This season seems like ...