The NFL is mandating that each team develop an Infectious Disease Emergency Response plan that sets forth the team's protocols for containing an outbreak of the coronavirus.

The edict was issued in a memo sent to all teams.

It 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.