A blindside block is a type of block in football where a player blocks an opponent who is not looking at them or in the direction away from the action of play. Blindside blocks can be extremely dangerous and lead to serious head injuries, which is why they were eliminated from legal play in 2019. According to Rule 12-2-7, it is a foul if a player initiates a block when his path is toward or parallel to his own end line and makes forcible contact to his opponent with his helmet, forearm, or shoulder. However, there is an exception to this rule: it is not a foul for a blindside block if the forcible contact occurs in "close-line play" prior to the ball leaving that area. The defensive player in pursuit of the runner, who does not have a reasonable opportunity to see the oncoming blocker, is considered defenseless. In keeping with putting player safety first, national rules now allow blocking from the blindside only when contact is initiated with the hands. An illegal blindside block is when a player makes a block while running towards or parallel to his own end line and makes forcible contact with his helmet, shoulder, or forearm to his opponent. An illegal blindside block results in a 15-yard penalty and possible ejection from the game.