Glendale police say the 31-year-old man was pronounced dead at a hospital after being seriously injured Wednesday. The man's identity was not released.
Police Sgt. Dave Viadure said the incident appeared to be a workplace accident.
The Arizona Division of Occupational Safety and Health is investigating. Division spokeswoman Rachel Brockway said state law prohibits release of any information until the investigation is completed.
NFL spokesman Brian McCarthy said the worker was hired through a subcontractor to help assemble the stage for the NFL Tailgate Party.
McCarthy said the man fell approximate 25-30 feet. He declined to release any additional information.