Related Clues:

• Desk-borrowing worker
• Sub at the office
• Short-term office worker
• Certain sub
• Seasonal employee
• Worker for a few weeks
• Workplace sub
• Irving Berlin's 'Blue --'
• Day-to-day worker, briefly
• Help for a while
• Crunch-time helper
• They're blue when clear
• Sidewalk Santa, e.g.
• Fill-in at the office
• ER stat