The referee replies Former NFL referee Jerry Markbreit describes the difference between offsides, encroachment, false start and illegal motion penalties in this week's installment of answers to readers' e-mail questions. Metrik, Chicago None of the above fouls are interchangeable, Matt, but some have the same signals, which adds to some confusion. Illegal shift has the same signal, with both hands moving away from the chest. It is a five-yard penalty and the down is replayed.
Encroachment is when a defensive player makes contact with an offensive player prior to the snap.
This foul prevents the play from starting and is a five-yard penalty from the line of scrimmage. A false start is when any offensive player makes a quick movement prior to the ball being snapped. It is also a false start when any down lineman makes any movement simulating the start of a play. False starts shut everything down and even if the ball is snapped, the play does not count. The referee will announce that there was a false start prior to the snap.