The NFL on Monday issued a warning to coaches across the league about wearing face coverings properly after several ignored established guidelines in last weekend's opening round of fixtures.
In a memo sent to all 32 teams across the league, NFL executive vice president of operations Troy Vincent said individuals who violated the face covering Covid-19 protocols risked "accountability measures."
"We must remain vigilant and disciplined in following the processes and protocols put in place by not only the league, union and clubs, but also by state and local governments," Vincent wrote in the memo.
"The NFL-NFLPA Game Day Protocol, which reflects the advice of infectious disease experts, club medical staffs and local and state governmental regulations requires all individuals with bench area access (including coaches and members of the club medical staff) to wear face coverings at all times.
"Failure to adhere to this requirement will result in accountability measures being imposed against offending individuals and/or clubs.
"The face covering must be worn as designed so that it securely fits across the wearers nose and mouth to prevent the transmission of the virus."
During Sunday's opening round of fixtures, several coaches were caught on camera either wearing face coverings inconsistently or not at all.
Los Angeles Rams head coach Sean McVay was repeatedly seen with his mask around his neck and not covering his face as he addressed players during their win over the Dallas Cowboys.
Las Vegas Raiders coach John Gruden also left his covering around his neck, as did New Orleans Saints coach Sean Payton and Detroit Lions boss Matt Patricia.