Coaches have taken to using their laminated list of plays to cover their mouths when sending in instructions. Some, such as Tampa Bay's Jon Gruden, cover almost their entire face.
There is some logic to that. Ernie Accorsi, general manager of the New York Giants, was the assistant GM with the Baltimore Colts in 1977 when the team hired Bob Colbert as an administrative assistant. Colbert was a former head coach at Gallaudet, the leading university for the deaf and hard of hearing, and was a professional lip-reader.
"We didn't hire him for that reason, but lip-reading was his expertise," Accorsi said.
In the 1977 regular-season finale, a do-or-die game against New England, Colbert trained his binoculars on the Patriot defensive coordinator and saw him mouth the words "double safety blitz."
"We got that in to [quarterback] Bert Jones and he hit Raymond Chester down the middle for a 78-yard touchdown," said Accorsi, whose team won the division and got into the playoffs with that win.