Romero needed to strip down naked on his first weigh-in attempt but tipped the scales at 186lbs [one pound over]. The main event is positioned on top of arguably the most exciting card of action the UFC have put together this year.
"I don't think he can change that drastically at his age and in this little amount of time before the fight", he said.
Whittaker was named the official middleweight champion after Canadian fighter Georges St-Pierre vacated the title after his win over English fighter Michael Bisping in November a year ago at UFC 217.
No title fight for the main event but talks are ongoing about salvaging the fight. However, Romero is no longer eligible to win the title.
The fight will still take place, and Whittaker will retain his title if he wins.
"This fight, as far as I'm concerned, I have 25 minutes to try to finish him - and I'm going to use every single second of those minutes to try to achieve that".
"Interesting question", CM Punk noted. Romero said the commission ended up giving him just one hour, not two, to cut to the weight limit, and he received no explanation for the shortened opportunity.
Earlier this year, Romero weighed in at 187.7 pounds for a fight with Luke Rockhold for the interim belt. "I don't know why the commission didn't give me two hours".