August 22-25 Third Preseason Weekend.
August 27 Prior to 4:00 p.m., New York time, clubs must reduce their rosters to a maximum of 75 players
August 28 All tryouts on this date and for the remainder of the season must be reported to the League
August 29 Final Preseason Games.
August 31 August 31 -- Prior to 6:00 p.m., New York time, clubs must reduce rosters to a maximum of 53 players on the Active/Inactive List.
August 31 Simultaneously with the cut-down to 53, clubs that have players in the categories of Active/Physically Unable to Perform or Active/Non-Football Injury or Illness must select one of the following options: place player on Reserve/Physically Unable to Perform or Reserve/Non- Football Injury or Illness, whichever is applicable; request waivers; terminate contract; trade contract; or continue to count the player on the Active List.
September 1 Claiming period for players placed on waivers at the final roster reduction will expire at 12:00
September 1 Beginning at 12:00 p.m., New York time, clubs may establish a Practice Squad of eight players by signing free agents who do not have an Accrued Season of free agency credit or who were on the 46-player Active List for less than nine regular season games during each of any Accrued Seasons. A player cannot serve on the Practice Squad for more than three seasons.
September 1 Final day of preseason training camp for all clubs, as defined in CBA Article 23, Section 9.
September 3 After 4:00 p.m., New York time, a club is permitted to place a player on Reserve/Injured as "Designated for Return."
September 4 At 4:00 p.m., New York time, deadline for all NFL Player Contracts, Practice Player Contracts, tender offers, and miscellaneous amounts to fit within each Club’s 2013 Salary Cap, in anticipation of the midnight expiration of the Top 51 Rule.
September 5 At 12:00 a.m., New York time, the Top 51 Rule expires for all NFL Clubs.
September 5, 8-9 Regular Season opens.
September 24 Beginning on the Tuesday following the third weekend of regular season games, the claiming priority is based on the inverse order of the standing of clubs in the current season’s games.