Safety, historically known as a safetyman, is a position in gridiron football played by a member of the defense. The safeties are defensive backs who line up from ten to fifteen yards from the line of scrimmage who can play as linebackers or deep as normal safeties. There are two variations of the position in a typical American formation: the free safety (FS) and the strong safety (SS). Their duties depend on the defensive scheme. The defensive responsibilities of the safety and cornerback usually involve pass coverage towards the middle and sidelines of the field, respectively. While American (11-player) formations generally use two safeties, Canadian (12-player) formations generally have one safety and two defensive halfbacks, a position not used in the American game. As professional and college football have become more focused on the passing game, safeties have become more involved in covering the eligible pass receivers.
Safeties are the last line of defense; they are expected to be reliable tacklers, and many safeties rank among the hardest hitters in football. Safety positions can also be converted cornerbacks, either by design (Byron Jones) or as a cornerback ages (Charles Woodson, DeAngelo Hall, Lardarius Webb, Tramon Williams).
Historically, in the era of the one-platoon system, the safety was known as the defensive fullback (specifically the free safety; the strong safety would be a defensive halfback, a term still in Canadian parlance) or goaltender.