What is the Sideline in Football?
The sideline in football the boundary line that separates the field of play from the out of bounds area. Players, coaches, medical personnel, and the media all stand on the sideline. The sideline is marked as thick white turf, like the yard lines, on the edge of the field. The sideline is considered out of bounds.
In play, if a player steps onto the sideline with possession of the ball, they are called down. Moreso, if a player catches the football and lands on the sideline before landing in-bounds, the pass is called incomplete. An offensive player may not step on the sidelines while in play and rejoin the play, such as catching a pass, but a defensive player may rejoin the field of play after stepping out of bounds.
There are seven linesmen who cover the field during a game. The side judge, down judge, line judge and the field judge are positioned on the sidelines as officials. They all have different roles, like making sure the players don't step out of bounds and calling when the ball is dead.