With training camps scheduled to begin next month, the NFL is mandating that each team develop an Infectious Disease Emergency Response (IDER) plan that sets forth the team's protocols for containing an outbreak of the coronavirus, according to a memo sent to all teams obtained by ESPN.

The memo mandates that teams divide their organizations into "tiers" that define where personnel can go and what they can do. The tiers are designed to limit access to restricted areas such as the practice and stadium fields, sidelines, locker room and training rooms to essential personnel only. Teams must assign tiers to all their employees, who wear a tiered photograph credential to spell out their access.

NFL teams have spent recent days trying to figure out who to place in what tier, according to league sources. NFL teams must designate their Tier 1, Tier 2 and Tier 3 employees and turn the plans into the league office seven days before the first mandatory reporting date for players for the 2020 NFL season. No one quite knows when that reporting date will be, but 26 teams are scheduled to begin training camp July 28.

There already have been heated discussions within teams as to who ends up in which tier, sources told ESPN, as the teams' personnel try to cement their positions in the protocol.

Each team's IDER will be subject to review and approval by the NFL, NFLPA and the Infection Control for Sports, formerly known as the Duke Infection Control Outreach Network.

Each list must include the individual's first name, last name, title, role and requested access tier. The NFL then will review the lists and either approve or require revisions. Any proposed change to a club's list must be submitted to, and approved by, the NFL.

• Tier 1 will consist of players, coaches, trainers, physicians and necessary personnel who must have direct access to the players.

• Tier 2 will consist of general managers, football operations employees, other assistant coaches, video personnel, security and other essential personnel who may need to be in close proximity to the players and other Tier 1 individuals who may need to access restricted areas. Only individuals assigned to Tiers 1 and 2 will be permitted access to restricted areas, and there will be limits on the number of individuals from each team that can be assigned Tier 1 and Tier 2 access at any given time.

• Tier 3 will consist of certain operational personnel, in-house media and broadcast personnel, field manager, transportation providers and individuals who perform essential facility, stadium or event services but do not require close contact with Tier 1 individuals. Team and other personnel who work exclusively in areas of team facilities that are or will be completely cordoned off from the rest of the facility do not need to be credentialed in one of the three access tiers.

But the NFL now is forcing teams to establish a tier system that has become the unofficial summer preparation for the start of camp, whenever that begins.

The league and players' union sent a series of memos to teams outlining procedures for return. For instance, teams must create a separate entrance for Tier 1 and 2 members, and if one is not available, they must designate times for entry of different tiers through one entrance.

Personnel with access to restricted areas must undergo daily testing and answer a series of questions designed to assess whether the individual has been exposed to the coronavirus or has exhibited symptoms.

Social distancing and cleaning protocols also are spelled out in memos sent to the teams. Masks are required in facilities unless they interfere with athletic performance.

Teams are required to educate Tier 1 and 2 individuals about everything from the symptoms of coronavirus to mitigation of risk of exposure to media and fan interactions. Educational materials also will be made available to the families of players/staff.

The NFL and NFLPA say they may perform surprise inspections of sites to ensure compliance with the protocols.