Whittaker became the interim champion with a win over Yoel Romero at UFC 213 and he was set to make his first official title defense at UFC 221 on February 10, in his home country of Australia but unfortunately, that fight will no longer be happening.
Whittaker was an obvious choice to headline the event, as he is the first Australia-based champion in UFC history.
"I've been ruled medically unable to compete and won't be able to defend on home soil". The new main event at UFC 221 will still have championship gold resting in the balance as Rockhold vs. Romero will fight for an interim strap with the victor facing Whittaker in a unification bout later in 2018.
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. In a very active division, Rockhold and Romero have never faced each other. "With the change in the main event, customers may request a full refund of purchased tickets at point of sale".
Former champion Rockhold returned to action at UFC Fight Night 116 in September of 2017, ending the fifteen-month hiatus that followed his first-round stoppage defeat to Bisping at UFC 199 and the loss of his middleweight crown. This fight at UFC 221 will be the second interim title in that division in the past year. St-Pierre opted to vacate the championship just 31 days later, citing health reasons.