UFC 290 fighter Josiah Harrell withdraws due to rare brain disease ahead of fight debut

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Josiah Harrell was forced to withdraw from Saturday's highly anticipated UFC 290 event.

On Friday, Harrell was removed from the event due to what the promotion initially described as a "medical issue." But several hours after Harrell's scheduled promotional debut against Jack Della Maddalena was canceled, his manager shed some new light on the fighter's medical situation.

Maurice Blanco of First Round Management revealed that Harrell had been removed after scans had discovered an abnormality during a routine pre-fight brain MRI.

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Josiah Harrell poses on the scale during the UFC 290 official weigh-in at UFC APEX on July 7, 2023, in Las Vegas, Nevada. (Jeff Bottari/Zuffa LLC via Getty Images)

Harrell was diagnosed with moyamoya disease, which is "a rare blood vessel disorder in which the carotid artery in the skull becomes blocked or narrowed," according to the Mayo Clinic.

Blanco noted that Harrell's MRI "may have saved his life." He also mentioned that Harrell will likely undergo brain surgery in the near future.

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Harrell did not know he suffered from the disease, according to Blanco. He had been set to make his MMA debut at UFC 290.

The Octagon at UFC APEX on November 20, 2021, in Las Vegas, Nevada. (Chris Unger/Zuffa LLC)

Blanco also expressed gratitude for the UFC and the Nevada Athletic Commission's medical testing requirements. 

He noted that while Harrell had fought in three other states during his professional career, he was not required to undergo any pre-fight medical