Citing an eye injury, super middleweight titlist Mikkel Kessler of Denmark pulled out of the Super Six World Boxing Classic on Wednesday, putting his career in question and throwing the tournament into disarray as it heads into the home stretch.
Kessler's withdrawal means his Sept. 25 title defense in Herning, Denmark against American Allan Green -- who is already in training camp, according to promoter Lou DiBella -- is off.
"This is the most disappointing moment of my boxing career," said Kessler, who regained a piece of the 168-pound title with a close decision against Carl Froch in their second-round tournament bout on April 24. "After defeating Carl Froch, I was on the way to win the tournament, so pulling out now really hurts.
"The eye problem has bothered me since the beginning of the Super Six in my preparation for the bout against Andre Ward. It also bothered me in the fights against Ward and Froch, and in my training for the fight against Green it has become unbearable. I have consulted leading experts in Denmark and Germany and they have advised me to take a break from boxing so that the problem can heal."
Kessler lost a belt via a lopsided 11th-round technical decision to Ward in November in their tournament opener. Despite the setback, Kessler said he will be able to continue boxing after a break. He is expected to be out of action for about nine months.
"I have been assured that it will heal completely and that I will be back in the ring next year," Kessler said. "As a fair sportsman, I do not want to delay the Super Six, which is still the best thing that has happened to boxing for a long time. I wish my fellow contestants the best of luck -- may the best man win. I will be there to fight the winner in 2011."
Said Kalle Sauerland, Kessler's promoter: "You can recover from losing in the ring but you cannot recover from losing your health. There is nothing that is of bigger importance than the boxer's health. As much as we regret to see Mikkel pulling out, he was left with no other choice.
"He should take all the time in the world to recover. He can take comfort in the fact that he looked reborn in his last bout. Once he is recovered, he will continue where he left off. The 'Viking Warrior' will be back."
Kessler (43-2, 32 KOs) suffers from "a weakness of the superior oblique muscle of his left eye," according to eye specialist Dr. Gerhard Lang. "To continue boxing, the muscle needs a proper rest, meaning no fighting or sparring for nine months. After this break, a complete recovery is expected."
Kessler, 31, who was the favorite to win the tournament when it was announced, is the second fighter to pull out of the high-profile modified round-robin tournament involving six of the best super middleweights in the world. Former undisputed middleweight champ Jermain Taylor pulled out after suffering a massive 12th-round knockout loss to Arthur Abraham in their opening-round bout last fall.
Showtime's Ken Hershman, the mastermind of the tournament, said the show will go on despite Kessler's withdrawal.
"I commend Mikkel Kessler for his decision," Hershman said. "He has made a wise choice in light of his doctors' recommendations and he is showing tremendous respect for his fellow competitors and for the tournament format itself.
"We will publicly address how this turn of events affects the tournament in the coming days. I assure you we will make the best of this scenario. In fact, I have been aware of Mikkel's situation for a few days and I have a vision for how we can proceed that will enhance the excitement of the tournament. First, I must have some internal discussions but mark my words, the drama of the Super Six will be unrelenting and we will crown a champion in the early part of 2011."
One possible scenario under discussion, according to two sources familiar with the situation, is that Group Stage 3, the last of the round-robin portion of the tournament, will be eliminated and the event will move directly to the semifinals.
That would mean that Ward's title defense against 2004 U.S. Olympic teammate and friend Andre Dirrell would be for a berth in the final, as would Froch's bout with Abraham.
Ward-Dirrell is scheduled for Sept. 25, but with tickets not on sale, no site announced and no press conference scheduled, few believed the fight was going to happen then anyway. The fight figures to be delayed closer to the end of the year, or even into early 2011.
Abraham-Froch is scheduled for Oct. 2 in Monte Carlo.
If those two bouts become the semifinals, it would keep the final on schedule to take place as originally planned in the spring or early summer. It would also involve the four healthy fighters with the most points in the tournament.
Fighters are awarded two points for a win, a third point if they win by knockout, one point for a draw and no points for a loss.
Ward, who is 2-0 in the tournament and has four points, had already secured a semifinal berth. Abraham, 1-1 in the tournament with three points, Froch and Dirrell are both 1-1 with two points apiece.
Green's status would be unclear if the tournament moves directly to the semifinals, although he had no points after a one-sided loss to Ward in June as Taylor's replacement. Although mathematically alive for a semifinal berth, his chances of advancing were slim.
Lou DiBella, Green's promoter, said he hoped his fighter would not be left out in the cold by Showtime.
"Obviously, all of Team Green is bitterly disappointed about not getting the opportunity to travel to Denmark for this great challenge," DiBella said. "It is hard not to feel for Allan Green. This is the third training camp in the last year that he has had interrupted for various reasons beyond his control.
"In the coming days we will sit down with Ken Hershman to discuss Allan's future. We trust that Showtime will provide Allan with the opportunity to showcase his skills in a meaningful fight versus a world-class opponent in the very near future."
Sauerland told The Associated Press that he had a "a verbal agreement" for a fight next year between Kessler and the winner of the Super Six.
Dan Rafael is the boxing writer for ESPN.com. Follow him on Twitter @danrafaelespn.