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.
Robert Whittaker, left, punches Yoel Romero in their interim UFC middleweight championship bout in Las Vegas, in July.
Whittaker's injury with a new interim title being introduced is just the latest saga affecting the middleweight division.
"I'm beyond disappointed that I'm unable to defend the title in my home country of Australia", Whittaker said.
Romero last fought and lost to Whittaker in a five-round contest that put Whittaker in the history books as Australia's first UFC champion. 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.
Regardless, Rockhold will continue his climb back towards the title by facing Romero, who was scheduled to take on David Branch on February 24, for the interim title. Customers who purchased tickets are eligible for a full refund.
In the long term, UFC 221 had the potential to be a promotional flawless storm similar to UFC Dublin, which cemented Conor McGregor as one of the UFC's top stars.
The switch is yet another odd turn in the UFC's middleweight division. In the weeks that followed St-Pierre's triumphant return to the cage after more than four years away from the Octagon, "GSP" announced a medical condition would prevent him from competing for a lengthy stretch. Those wins included victories over Chris Weidman, Ronaldo Souza and Lyoto Machida.