Cain Velasquez will not fight at UFC 207 due to an undisclosed health issue, MMAFighting.com reported.
A spokesman for the Nevada Athletic Commission told Ariel Helwani that Velasquez is "unfit to fight."
The former UFC heavyweight champion was scheduled to face Fabricio Werdum on Friday in Las Vegas.
The report said it's likely Velasquez's issues are related to chronic back pain and other back-related injuries.
"It's obvious Mr. Velasquez is physically compromised and that would place him at significant physical disadvantage in the fight," NAC executive director Bob Bennett said. "Therefore, we've gone ahead and suspended his license due to medical reasons."