The NFL has sent a memo instructing all 32 teams to develop a method for identifying players, coaches, and employees who have received the coronavirus vaccine.

In a five-page memo released last week and obtained by Pro Football Talk, the league informed teams of a requirement to develop  a system for identifying fully-vaccinated “Tier 1 and Tiers 2 personnel.”

Players and coaches fall under the Tier 1 category.

“We recommend utilizing color coded wristbands or credentials, however clubs are free to implement other methods,” the memo stated.

While identifying personnel who have been vaccinated, such a system would also make obvious which personnel have not been vaccinated. The NFL has aggressively encouraged its players to get vaccinated but has stopped short of requiring it. Most teams have well over 50 percent of their rosters vaccinated. In contrast, only Washington and Indianapolis remain below 50 percent.

In addition, the league has set forth numerous restrictions on player-coach interaction for teams with less than 85 percent of their players and staff vaccinated.