August 13-17: First preseason weekend
Sept. 1: Clubs must reduce their active rosters to 75 players by 4 p.m. Eastern Time.
Sept. 3: Final preseason games
Sept. 5: Clubs must reduce their rosters to 53 players by 4 p.m. Eastern Time.
By the same deadline, teams who have players listed as “Physically Unable to Perform” or “Non-Football Injury or Illness” must either place the player on a reserve list, waive the player, terminate the contract or count the player as one the 53 on the active roster.
Sept. 6: Players waived during the final cut-down can be claimed until noon Eastern Time.
After that waiver period expires, teams may build a 10-man practice squad.
After 4 p.m. Eastern Time, a team may place a player on the injured reserve with a designation to return.
Sept. 10: At 12:00 a.m., New York time, the Top 51 Rule expires for all NFL clubs. After this point, the salary cap will now include all players on the active roster, rather than the “top 51.”
Sept. 10, 13-14: Regular season begins.
http://www.nola.com/saints/index.ssf/2015/07/nfl_calendar_key_dates_for_201.html
Agamemnon