 Most of the time, when you watch a football game, you'll see a setup that's something like this. Only on TV, it'll be from this side, but we're going to look at it this way because this is American football and it's a free country. Also it's easier to see this way. Anyway, the ball is here. It creates this line called the line of scrimmage. Before the ball is snapped, nobody on either team can cross the line of scrimmage. If they do, they're never allowed to play football again in their life. Well, not really, but their team does get a penalty. So offense here, defense here. The offense has the ball, the defense is defending their end zone. These five guys are the offensive line. This middle guy here, he's called the center. We don't know why he's called the center, that's been lost to history. The guys on his right and left are the guards, because they are guarding the quarterback. The guys on the ends are the tackles. Not this tackle, not that tackle, just the left and right tackles. These five guys on the offensive line have one job, imitate the Great Wallet China. The defense will be trying to get the guy with the ball, and their job is to stop them. So they're usually the biggest guys on the field. Each play starts with the center snapping the ball back to the quarterback. The quarterback is this guy. He is considered to be the most important player. Some say the quarterback is the most important position in all of sports. If you live in the United States and you know nothing about football, you've almost certainly heard of a quarterback. Joe Namath, Dan Marino, John Elway. Being a quarterback is what Peyton Manning did before he made commercials. It's what Aaron Rodgers did while he made commercials. Giselle Bunchen's husband is a quarterback. So why is this guy so important that he gets to sell us insurance once he retires? The offense is going to do one of two things on every play. Run the ball, or pass the ball. If it's a run, it's actually kind of easy for the quarterback who just has to turn around and hand it or toss it to one of these guys back here. These are the running backs. There are two types of running backs, the half back and the full back. If you guessed that the half back would be the guy half way back and the full back is the other one, you would be a rational person. You would also be wrong. Why is that? Back in the day, they used to have a formation that looked like this. So the quarterback, the half backs, and the full back. The quarterback would throw the ball, half backs ran the ball, and the full back blocked defensive players. At some point, someone who I can only imagine went on to win the Nobel Prize said let's not put the guy whose job it is to block as far from who he's supposed to block as possible. So the full back got moved up, the half back moved back, but they kept their names. Anyway, sometimes the quarterback will hand off to the full back, but usually it's to the half back. The full back is usually the bigger of the two, and the half back will be the faster one. The reason quarterbacks are the leader though, is passing. They will pass to their wide receivers who are these guys out here. They're usually really fast. Their job is to catch the ball when the quarterback throws it to them and run. If they're out wide, they're a wide receiver. If they're between a wide receiver and the line, you might hear them called a slot receiver, which brings us to the last offensive position, the tight end. The tight end is kind of a half wide receiver and half offensive lineman. Sometimes they'll try to catch a pass, other times they'll block. So the quarterback is trying to throw the ball to the right receiver, avoid throwing it somewhere where the defense can block or catch it themselves, all the while avoid getting tackled by the defensive line, which is why being a quarterback is kind of a tough job. There's always going to be 11 players on the side, but they don't necessarily have to stand in these spots. You always have your five lineman. You need at least seven guys up on the line of scrimmage. You need somebody back here for the center to snap it to. And there are certain rules about who can catch a pass based on where they're lined up that we won't get into here. But other than that, you can use your left brain. You can have three wide receivers, or four, or even five. You can have two tight ends. You can move your quarterback back. You can even get involved in a land war in Asia if you want, although I don't recommend that last one. So center, guards, tackles, or the offensive line, we have the quarterback, the fullback, and the halfback are the running backs. We have the wide receivers, and we have a tight end. That's offense. Opposite the offensive line is the defensive line. This team is using what's called a 4-3 defense, which is the most common setup in the NFL today. This means that they have four guys on their defensive line. The two guys inside are the defensive tackles, and the two guys on the outside are the defensive ends. Like the offensive line, the guys in the defensive line will probably be the biggest guys on the field for the defense. The 3-4-3 is for the three linebackers, who are these guys right behind the linemen. The one in the middle is the middle linebacker, and the other two are the outside linebackers. These guys are a balance between being big and being fast. They're probably going to be the strongest guys on the field for the defense. The fastest players on the defense will be the defensive backs or the secondary. First are the cornerbacks, not to be confused with the quarterback, who will line up across from the wide receivers. And then the safeties, who are the last line of defense. There's usually a strong safety who will be a little closer to the line, and then there's a free safety who's running around to help the cornerbacks with deep passes. Other than the 4-3, the other common setup is the 3-4, which just means that there are three linemen and four linebackers. This creates this middle lineman who is called the nose tackle. Unlike the offense, there's not really anything required about where the defense stands, so anybody can move anywhere. You might see some teams in the 3-4 bring their outside linebackers up to the line and almost create a 5-2. So the linemen are the defensive tackles, defensive ends, and sometimes the nose tackle. Linebackers include middle linebackers and outside linebackers, and the defensive backs include the cornerbacks and the safeties. Rather than the offense and the defense, some plays are considered to be special teams, when one team is kicking the ball to the other in one way or another. Kickoffs, field goals, extra points, and punts have some specialty positions. If you want to play football and keep the risk of injury to a minimum, listen up here. A kicker is a guy who will come out and kick the ball during kickoffs, field goals, and extra points. That's it. It's usually a penalty if the defense hits him while he's kicking, which is why even though they never score touchdowns, the guys who have all scored the most points in NFL history have all basically been kickers, just because they can play for so long. The guy holding the ball for the kicker while he's kicking field goals and extra points is aptly named the holder. A lot of the time, he'll be a backup quarterback. He catches the ball from a special replacement of the center called the long snapper. The long snapper will also snap the ball to the punter who comes out to punt the ball for the offense. If you're punting a ball, that means you're kicking it, but nobody's holding it, so you're just dropping it and kicking it. Standing at the other end of the field to receive the kickoff for the punch is the returner, who's usually one of the fastest guys on the team, sometimes he's a wide receiver. It's his job to catch the kick or the punt and run it back as far as he can before he gets tackled. Each team will have its own different set of players to play offense, defense, and special teams. Players can sub in and out between each and every play, and often they do. Players are allowed to play any position at any point, but generally every player has one or two positions that they'll stick to. It's only occasionally that they'll play more than one in a game.