Operates
on same side of field as Linesman, 20 yards deep. Keys
on wide receiver on his side. Concentrates on path of
end or back, observing legality of his potential
block(s) or of actions taken against him. Is prepared
to rule from deep position on holding or illegal use
of hands by end or back or on defensive infractions
committed by player guarding him. Has primary
responsibility to make decisions involving sideline on
his side of field, e.g., pass receiver or runner in or
out of bounds.
Side Judge makes decisions involving catching,
recovery, or illegal touching of a loose ball beyond
line of scrimmage; rules on plays involving pass
receiver, including legality of catch or pass
interference; assists in covering actions of runner,
including blocks by teammates and that of defenders;
and calls clipping on punt returns. On field goals and
point after touchdown attempts, he becomes a double
umpire
