Romero missed weight by 0.2lbs overnight - his second straight failed weight cut - removing the title from the equation.
No title fight for the main event but talks are ongoing about salvaging the fight.
"We came here to fight for the title", Romero said after the ceremonial weigh-ins, where he received a chorus of boos from the local crowd "I came here for the title fight".
The fight will still take place, and Whittaker will retain his title if he wins.
Expect no letup in Halep-Stephens final
There is no-one else I'd rather lose to than the number one in the world", Stephens, who will rise to four in the rankings, said. She broke to grab the second set when Stephens sailed a backhand wide, all part of a seven-game run that made it 5-0 in third.
Alligator may have bitten, killed woman in Florida, authorities say
Matsuki's husband, who is out of town, has been told his wife went missing after walking the dogs, the paper reported . From 1948 to 2017, 401 unprovoked bite incidents have occurred in Florida with 24 of these proving fatal.
Anthony Bourdain's death impacts local community
It is now the 10-leading cause of death in the USA , and is one of only three leading causes of death that are on the rise. Cultural attitudes may play a part . "We have to keep working on stigma", Zietlow-DeJesus said.
He didn't have enough for Mike Jackson (1-1 MMA, 1-1 UFC), though, who earned a unanimous decision victory over Punk and likely ended the UFC tenure of the former pro wrestling standout. It's not only a fight for a fight - I want to fight for the title.
Given that he was competing for the UFC belt, he had to make "championship weight" of 185lbs or under. It would make me upset if my opponent missed weight because I believe making weight is half the job; if you don't make 84.5 [kilos, 186lbs] then we're not in the same weight division.
In what was supposed to be his first title defence, Australia's first UFC champion will face the man he fought and beat in his last outing.
The hugely divisive Colby Covington takes on Brazilian Rafael dos Anjos having called Brazilians "filthy animals" and CM Punk of WWE fame steps into the octagon for the second time.
Camera IconCan Robert Whittaker overcome Yoel Romero? "I don't know what they're going to do".