A guard in football is an offensive lineman who is positioned on the line of scrimmage at the start of a down. There are left guards and right guards on the offense. Guards serve as blockers and counter defensive tackles (DT) of the defensive line. Guards should be skilled both offensively and defensively, but specialize in tackling. Since tackling is involved in two of their most important roles, the guards must quick to tackle in high pressure situations.
One of the main responsibilities of a guard is to protect the quarterback. This means blocking out the defenders who are trying to sack the quarterback. The right guard and left guard are in front of the quarterback on their respective sides and work to give the quarterback as much time as possible to think and act.
Blocking the defensive line members allows for the guards to create lanes for their teammates. Open holes on the field are available for running backs when the guards push their opponent out of their natural position. The guards main goal is to stop any defenders from encroaching upon the offense.