There is no set timetable for Peterson and Hardy on their return, as they may not even return this season. It isn't a guarantee that either of them will return to the team. Both Peterson and Hardy can still be released if they are convicted of the accusations.
Hardy played in the Panthers' week 1 win over the Buccaneers, and was expected to be active in week 2 against the Lions. Despite the charges, Carolina said that Hardy would play in week 2, much to the chagrin of the public. Sunday morning he was placed on the inactive list, and there is no doubt that the Vikings' decision with Adrian Peterson influenced the decision of the Panthers.
This was a decision that was agreed upon by both parties in both cases. The teams no longer need to go through the stress week after week on deciding whether they should play or not. The agent of Adrian Peterson says it was "the best possible outcome given the circumstances." Meanwhile, the decision to place Hardy on the list was agreed upon by the defensive end in a meeting with the team.