David Haye's world heavyweight title showdown against Wladimir Klitschko could be staged in late July, according to the Ukrainian's manager. Haye withdrew from his challenge on Wednesday night for Klitschko's IBF, WBO and IBO belts at FC Schalke's Veltins-Arena on June 20 because of an injury sustained in training. The nature or severity of the problem is unknown and the 28-year-old Londoner will see an independent doctor next week when a clearer picture of when the fight can be rescheduled should emerge. Klitschko may opt to fight a different opponent on June 20 but his manager Bernd Boente believes the Haye fight could still be held this summer. "Contractually we have to first of all see how bad the injury is," he told Setanta Sports News. "If there is just a small postponement, maybe we could do the fight four weeks later. "We have put a lot of training into the fight but we will have to see. "The first question they have to answer is when will they be ready again?" Klitschko has voiced his frustration at Haye's withdrawal but refused to question the validity of his injury. "I'm pretty frustrated right now. I've been waiting for this David Haye fight for half a year," said Klitschko. "But now I have no David Haye on June 20th, so we'll keep the date and I wish a fast recovery to him. "So now I have no opponent and will look for somebody else. I wish David Haye a fast recovery. "I would not throw garbage at a person who is on the floor, which would probably not be the case if this was the other way round."