The left tackle is widely considered to be one of the most important players on a team's roster. Since most NFL quarterbacks are right handed, they often have their backs turned to players rushing towards them from the left side of the field when trying to complete a pass. A good left tackle helps prevent the quarterback from being brought to the ground by a defender that is hard for the quarterback to sense coming.
Similar to other offensive linemen, a left tackle needs to have a large stature and exceptional strength. Nearly every left tackle playing in the NFL weighs approximately 300 pounds and stands well over six feet tall. This allows the player to fight off powerful defenders trying to shake off the blocker and take down the quarterback. Left tackles also possess exceptional foot speed in order to keep up with defenders rushing off the edge of the line, as edge rushers are often extremely quick and powerful.
Because left tackles are so crucial in ensuring the safety of the offense's quarterback, they often make higher salaries than other positions within the offensive line. Each of the top left tackles in the NFL make north of 14 million dollars per year compared to just one player at each of the other four offensive line positions (left guard, center, right guard, tackle).