Britain's Tyson Fury is searching for a new opponent for his 1 December heavyweight fight in Belfast after Russian Denis Boytsov withdrew.
Unbeaten Boytsov, 26, was set to face 6ft 9in Fury at Odyssey Arena in a WBC world-title eliminator, but now says he requires more preparation.
"Boytsov has decided against the fight so we are now in discussions with a few other possible opponents," Fury's management told BBC Sport.
"The fight could still happen in 2013."
Fury, 24, claimed the vacant WBO Inter-Continental heavyweight title by stopping American Vinny Maddalone in the fifth round of his last fight in Somerset in July.
He has won all of his 19 contests to date, 14 by knockout, and is targeting a shot at reigning champion Vitali Klitschko.
Lee Squirrel of Hennessey Sports, who represent Fury, said: "We were in discussions with Boytsov's management team, [but] it looks like they wanted more time to prepare.
"Tyson will still be fighting on 1 December at the Odyssey Arena."
Fury's uncle and trainer Peter later tweeted his team are focused on "looking for someone to fill in the void."
He added: "These things happen. It's been a frustrating two months."