Definition: The official who sets up 20 yards deep in the defensive backfield on the wide receiver side of the field. His duties include:
• Make sure the defensive team has no more than 11 players on the field
• Watch all eligible receivers on his side of the field
• Watch the area between the umpire and field judge
• Rule on the legality of catches and pass interference penalties
• Watch for clipping on kick returns
• On field goals, stand under the goalpost and rule on whether the kick is good