WBC super-middleweight champion Mikkel Kessler has been forced to withdraw from the Super Six tournament with an eye injury.
The Danish boxer is believed to have picked up the injury during his victory over Carl Froch in April, a bout which saw both men exchange some heavy blows in the 12-round contest.
The 31-year-old was scheduled to defend his newly won title against American Allan Green in September, while there had been talk he would face the winner of the Super Six tournament once it was completed.
However, Kessler's boxing career has been thrown into doubt with his latest injury and despite the fighter playing down the serious nature of the problem, he has hinted it could force him to retire.
Kessler said: "I have a few problems when I go down the stairs and when I close one eye, I don't see double. It means that I had to give up my big dream, but I am not throwing the towel in the ring."