Aspinall had been preparing for a November rematch with Ciryl Gane at UFC 334 before a sparring blow made his injured right eye “go back to square one,” forcing him to vacate the title.
Doctors later delivered a poor scan and would not clear the 33-year-old to fight, with Ariel Helwani reporting Aspinall may need more surgery and is now targeting January for a possible return.
The setback extends a layoff that began when eye pokes ended Aspinall’s first undisputed title defense against Gane at UFC 321 late in the first round.
With the belt vacant, interim champion Gane is now central to the division’s next move, with a title fight against Alex Pereira or unbeaten heavyweight Josh Hokit among the leading options.