The first high-profile bout to be bitten by the injury bug in 2018 is here.
UFC middleweight champion Robert Whittaker's homecoming fight in Australia is not going to happen.
It is a major blow for the event as the UFC take their first trip to Western Australia after the state recently had a ban on the cage lifted for MMA events. Romero has been out of action since his loss to Whittaker.
With just a month to go until the event, UFC officials have moved quickly to find a replacement for Whittaker, and so Yoel Romero will now step in to fight Rockhold for the interim middleweight title in the main event instead.
Prior to being drafted in to replace Whittaker, Romero had been scheduled to face former two-weight WSOF champion David Branch at UFC on Fox 28 in Orlando, Florida on February 24th - exactly two weeks after the Perth event.
Giorgi ousts Radwanska at Sydney International
Kerber, the 2016 Australian Open champion, won four consecutive singles matches at the Hopman Cup, followed by five in Sydney . She will meet the victor of another quarterfinal between defending champion Agnieszka Radwanska and qualifier Camila Giorgi.
Rockhold (16-3-0) is a former UFC Middleweight Champion, defeating Chris Weidman by fourth round TKO at UFC 194 to become champ. He is actually coming off a decision loss to Whittaker for the interim title last July.
"I've been ruled medically unable to compete and wont be able to defend on home soil".
It's an especially devastating hit for an already lacking pay-per-view, which features Mark Hunt vs. Curtis Blaydes in the co-main but not much else that would justify calling it a true pay-per-view-worthy event. "I hope the fans enjoy what should be a great night of fights at UFC 221, and I look forward to a recovery as soon as possible that will have me back in the Octagon to face the victor of the main event".
The switch is yet another unusual turn in the UFC's middleweight division. UFC officials told ESPN that Whittaker will face the victor in a unification bout.