Sheriff's Lt. Kent O'Donnell says the 57-year-old man had been traveling the country by bus and decided to take a rest three rows deep in a field on the outskirts of Billings, the state's largest city.
A farmer harvesting Wednesday felt his combine hit something. When he turned the machine off, he heard screaming.
Emergency responders found the man's clothing had been sucked into the cutter, ensnaring him in the blades.
The sheriff says the man, whose name was not released, suffered cuts requiring stitches and may need skin grafts, but given the circumstances is "incredibly lucky."