Following this win, Thompson stayed inactive for almost seven months due to shoulder injury before returning to the ring on November 20, facing an American journeyman Paul Marinaccio on the undercard of the rematch between Paul Williams and Sergio Martinez. During his preparation, Thompson was one of the main sparring partners for then-WBA world heavyweight champion David Haye, who was training for his title defense against Audley Harrison. For the fight, Marinaccio had lost 17 pounds and weighed in at 228 lb, his lightest since 2005. Thompson made a quick work of Marinaccio, ultimately stopping him in the fourth round. Following that, Thompson, who was ranked No.7 by IBF, reached agreements to face No.6 ranked Maurice Harris in an IBF world heavyweight title eliminator for the No.2 spot. The fight was supposed to open an ESPN2 "Friday Night Fights" telecast headlined by Josesito Lopez vs Steve Upsher Chambers but was moved to the main event after Lopez pulled out due to injury. For the fight, Thompson weighed in at 255.5 lbs, the second heaviest in his career up to that date. Thompson defeated Harris by third-round TKO, moving to the No.2 IBF contendership spot. After the fight, Harris filed an official complaint against Thompson, claiming that he was hit with more than 20 illegal rabbit punches in the second and third rounds. Harris complained about his equilibrium was off after he was floored in the second round by a right hook that, according to Harris, landed behind the head. The replay, however, showed no signs of rabbit punching in the right hook that sent Harris down.