He ascended to the undisputed middleweight championship after claiming the interim belt with a five-round unanimous decision victory over Romero as a minus-125 chalk at UFC 213 that extended his win streak to eight fights going into Saturday night's matchup at the United Center in Chicago.
Romero, 41, weighed in at 186 pounds in his first attempt Friday.
Earlier in the week, Whittaker was asked whether he would take the fight if Romero missed weight again. Romero won that bout via a knockout, and although he wasn't awarded a belt, he immediately was given a title shot despite his weight cutting issues. "Absolutely it's on. (Romero) missed by 0.2 (lbs)", White said on the official weigh-in broadcast.
Now recovered from a staph infection and a nasty case of chickenpox, Whittaker is ready to get back in the Octagon with the "Soldier of God". Or really punish him for missing weight by pushing him down the line of contenders.More news: May finds cabinet compromise with Brexit fall-back plan
The Cuban has tipped the scales before, last time in February for a fight in Perth.
"I don't think he can change that drastically at his age and in this little amount of time before the fight", he said.
Explosive Sydney heavyweight Tai Tuivasa weighed in nearly five and a half kilos heavier than former world champion Andrei Arlovski.