The 33-year-old Englishman said on Instagram on Monday that he had agreed a fight date and returned to sparring when another accident damaged his right eye.
“This means more time away from the sport, and right now, the timing of my return is unclear,” he wrote.
Aspinall has not completed a title defence since inheriting the belt from retired former champion Jon Jones. His first scheduled defence against Ciryl Gane at UFC 321 in Abu Dhabi in October 2025 was ruled a first-round no-contest after severe eye pokes left him unable to continue.
He has since undergone multiple surgeries and been treated for infections. He has also spoken of a diagnosis of Brown’s syndrome, a condition that restricts eye movement.
Aspinall said he asked the UFC to let him make the announcement so the division would not be held up. “I know what it’s like to have your career put on hold and I want the other fighters to have the opportunity to compete for the title.”
Gane won the interim heavyweight title by stopping Alex Pereira in June. Relinquishing the undisputed belt clears the way for the Frenchman to be elevated to undisputed champion.
Aspinall insisted he is not retiring. “Stepping away from the title is not stepping away from the sport or the dream,” he said. “I’m absolutely gutted. I’ve chased this dream since I was 10 years old. I’m not done.”
He added that he would keep working with doctors to get healthy and cleared. The timing of any return remains unknown.