Related Clues:

• Officiate a lacrosse game
• NLL official
• One calling a 'T'
• Expert with flags, perhaps
• WNBA arbiter
• Celtics game official
• Caller of fouls
• Soccer card holder
• Certain whistle-blower
• Rugby official
• Soccer official, informally
• Whistle blower, briefly
• The one who ensures fair play
• Whistle-blower hiding up in safe room
• Sporting man in black?