The offensive team must have at least seven players on the line of scrimmage at the time of the snap. There are no regulations regarding the number of defensive players on the scrimmage line.
While all 11 offensive players may be on the line, seven is the most common formation. Of the players on the line, only the two on the ends are eligible receivers. The receivers are either tight ends or wide receivers. Keeping the offensive line at the minimum of seven players allows for more receivers in the backfield. The penalty for having less than seven players on the line is 5 yards.