Per a source with knowledge of the situation, the Packers are telling players that the doors will open on Friday, and that the team wants the players in town in order to get started on preparations for training camp and the preseason.
This presumes that the remaining issues between the NFL and the NFLPA* will be resolved in time for the players and the owners to separately approve the new agreement. The fact that the Packers are getting the word out shows how widespread that presumption currently is.
From Pro football Talk. This follows the logic that the owners will vote and approve a deal on Thursday, meaning players could be allowed at team facilities as soon as Friday.