Romero, 41, weighed in at 186 pounds on his first attempt on Friday. The Illinois State Athletic Commission afforded him two additional hours to make the 185-pound weight limit, but Romero came up short at 185.2 pounds.
The UFC has not yet announced whether the fight will continue or what stipulations will be added.
It’s the second consecutive bout Romero (13-2) has missed weight. He was scheduled to fight Luke Rockhold for an interim title at UFC 221 in February, but came in at 187.7 pounds. The bout was eventually salvaged. Romero knocked out Rockhold in the second round.
Earlier in the week, Whittaker was asked whether he would take the fight if Romero missed weight again. He jokingly responded it’s a “long flight” from his home in Australia, and added, “I’m fighting somebody.”