In modern American football, the quarterback is usually considered the leader of the offensive team, and is often responsible for calling the play in the huddle. The quarterback also touches the ball on almost every offensive play, and is the offensive player that almost always throws forward passes.
The offensive line, or O-line, are the group of offensive players that play up front and block for the quarterback and running backs. Even though the quarterback and running backs get all the glory and press, they couldn’t do anything without the offensive line.
Running backs line up in the offensive backfield with the quarterback. They are the primary rushers on the team. They also catch short passes and provide extra blocking.
Receivers are offensive players who specialize in catching passes downfield. They are often some of the fastest players on the field. Receivers come in all sizes from small players well under 6′ tall to tall big players over 6′ 5″. The smaller players excel due to quickness, speed, and running precise routes. The larger players are able to out jump smaller defenders and present a big target for quarterbacks.