In American football, an signal is when the QB, just before the snap of the play, changes the pre-determined play at the line of scrimmage. Essentially, it's a sudden adjustment! The player might notice something on https://xem-bng-trc-tip-ko-nh-ci031245.mybjjblog.com/what-represents-an-play-call-in-football-a-look-54291314