4 offensive players will have to line up at stake of scrimmage. 3 defensive players have to be down linemen (in a three of 4-position stance). A person linebacker may well blitz on either side of the middle. Defensive linemen should line up no broader than shoulder to shoulder ("shading") https://leisurecityguide.wordpress.com/2024/08/29/the-thrills-and-benefits-of-indoor-football/