There seems to be some confusion among fans about the Packers salary cap space. The answer is they have $15.3 million or so in salary cap space. Their effective space is about $100K.
At present, the Rule of 51 is in place. Only the highest 51 contracts count against the cap. That will change in September when the season starts. At that time the Packers will have to account for contracts of the 52nd and 53rd players. They will have to sign players to the practice squad. In May and June, they will have to sign their draft picks.