Looking at how he will be replaced shows that Jordy Nelson's injury is far from a crippling blow for the Packers' offense.
It completely sucks to lose a player of Jordy Nelson's caliber for the entire season, and there's no getting around that. He is, in my opinion, one of the five best receivers in the league and is a huge weapon as the focal point of the Packers' passing attack.
With all of that said, if you have to lose a player and you have depth like the Packers do, you would want it to be a wide receiver, because wide receivers are just about the easiest things to replace in all of sports.