UFC on FUEL 6: Hyun Gyu Lim 'medically unfit' to compete

The UFC has since released an official statement about it, also mentioning that Mitchell will be getting paid:

After being examined by doctors it was determined that Hyun Gyu Lim was medically unfit to participate in tomorrow's event and as a precaution, his UFC Macao bout has been canceled. His opponent, David Mitchell, will be paid his show money.