Mormeck was dropped heavily in the 7th round after being hit by a strong right from Haye. Although Mormeck rose up just in time, the referee realized that he was dazed and in no condition to go on, which caused the contest to be stopped and Haye winning the fight by knockout. On 17 December 2009, Mormeck made his return to the ring after a two-year layoff, fighting for the first time as a heavyweight, against Vinny Maddalone. He outpointed the veteran heavyweight over 8 rounds. Mormeck fought Uzbek heavyweight and WBA#7 Timur Ibragimov (30-3-1, 16 KO) on 2 December 2010, at Halle Carpentier, Paris. Mormeck started slowly but dominated the middle rounds to win a split decision (116-112, 116-111, 113-115). In October 2011, Mormeck was signed to fight unified Heavyweight Champion Wladimir Klitschko on 10 December 2011 at Esprit Arena, Düsseldorf, Germany  until Klitschko pulled out after having a kidney stone removed on 2 December 2011. The fight was postponed to 3 March 2012. In this fight, Mormeck attempted to be only the third cruiserweight champion to win a world title at Heavyweight, after Evander Holyfield and David Haye. However, he was defeated by the 4th - round KO.