The man was at a tailgating event in a parking lot at Fairfield High Preparatory School when he was shot in the buttocks – the shots apparently coming from near an abandoned house – around 9.45 p.m., the office said from the Jefferson County Sheriff.
“Keep calm. Stay on the ground,” an announcer said over the public address system, as the players were lying on the pitch and on the sidelines. Some spectators ran while others sat or crouched in the stands amid cries of fear and concern.
The players were eventually asked to stand up and leave the field.
MPs searched the area but did not immediately find the shooter, the sheriff’s office said.
The gunshot victim was taken to hospital with a non-life threatening injury, according to the sheriff’s office.
Fairfield is just outside of Birmingham.
The remainder of the game has been postponed until Saturday, the sheriff’s office said.