Despite middleweight world titlist Billy Joe Saunders citing a hamstring injury and withdrawing from his defense against British countryman Martin Murray on Sunday, promoter Frank Warren announced Monday that the June 23 card at the O2 Arena in London will still take place.

"This is a massive blow, but the show must go on," Warren said. "I feel for the fans and for Martin, but if Billy is injured, there's no way he can fight. It's important we still deliver to the live and the TV audience and they can look forward to seeing many of London's finest boxing talents on June 23 at the O2 Arena."

The card, which will stream live on ESPN+ in the United States, could still include Murray against a new opponent and will still include fast-rising heavyweight prospect Daniel Dubois (7-0, 7 KOs), 20, of England, in a 10-round fight against Tom Little (10-5, 3 KOs), 30, of England, and light heavyweight up-and-comer Anthony Yarde (15-0, 14 KOs), 26, of England, against an opponent to be determined also in a 10-rounder.

Warren struck back at those who suggested that Saunders pulled out without having a real injury perhaps waiting to see what will happen with the rematch between unified world champion Gennady Golovkin and Canelo Alvarez. If it does not come off, Saunders would be an ideal candidate to fight either of them.

"I've seen rumors that Billy isn't injured, but he is a fighting man and there's no way he would pull out unless he had to," Warren said. "It's a shame after the devastating performance against (former titlist David) Lemieux last Christmas, as this was a chance for Billy to keep momentum as we continue to chase big fights for him. Martin may still feature on the card and we are working day and night trying to put something together. We will let the fans know news on this when we've had a chance to look at all options."

Ticket holders seeking a refund due to the change have 14 days to obtain one from their point of purchase, Warren said.

Saunders (26-0, 12 KOs), 28, and Murray (36-4-1, 17 KOs), 35, who was getting a world title shot for the fifth time, were initially scheduled to fight on April 14 but Saunders said he suffered a hand injury in training and the bout was postponed until June 23 before being called off again.

Saunders apologized for the situation on Sunday and did so again Monday.

"I am sorry to Martin and the fans for the inconvenience this has caused them. I know Martin has put himself through two hard camps now and I am hugely sorry that I've let both him and the fans down and prevented a great fight from happening," Saunders said. "It has been a tough time with injuries through the past few months but at this level against a top operator like Martin Murray you cannot risk going into a fight less than 100 percent. But I do appreciate the fans' support and I know Frank will be looking to get me back in the ring as soon as possible when I'm fit to fight."