Super middleweight champion Mikkel Kessler pulled out of the Super Six World Boxing Classic because of an eye injury Wednesday, which could cause the round-robin tournament to move straight to seeded semifinal matches.

The Dane, who defeated Carl Froch to win the WBC title in April, said his eyes had been "bothering me for some time" but that he would continue training. In the meantime, his defense against Allan Green scheduled for Sept. 25 in Herning, Denmark, has been canceled.

"I commend Mikkel Kessler for his decision," said Ken Hershman, vice president of tournament organizer Showtime. "He has made a wise choice in light of his doctor's recommendations and he is showing tremendous respect for his fellow competitors and for the tournament format itself."

The format of the Super Six was designed to give six of the best 168-pound boxers in the world three fights each, with points awarded based on their outcome. The four fighters with the most points would advance to the semifinals, with a championship bout scheduled for next year.

That process could skip forward now that Kessler has dropped out.

Andre Ward is the only fighter to win his first two bouts and leads the tournament with four points. Arthur Abraham has the only knockout and is second with three, while Froch is tied with Kessler and Andre Dirrell with two points each. Late substitute Green has zero.

The two other fights scheduled for the final stage of the round-robin already align with the current points standings, so tournament officials are considering making them semifinal bouts, a person with knowledge of the discussions told The Associated Press.

The person spoke on condition of anonymity because no official announcement has been made.

Ward would become the top seed and is already scheduled to face Dirrell on Sept. 25, while Abraham would become the second seed and is slated to face Froch on Oct. 2.

"We will publicly address how this turn of events affects the tournament in the coming days," Hershman said in a statement. "I assure you we will make the best of this scenario."

Moving straight to semifinals would deprive Green, a late substitute for Jermain Taylor, of a guaranteed fight. He's been considering a move to light heavyweight anyway and could step aside if he's guaranteed a high profile fight in the new weight class.

Whatever shakes out, the loss of Kessler is just one more kink in a tournament that began with good intentions but has been forced to adapt on the fly.

Taylor pulled out after only one fight, a brutal knockout loss to Abraham, and several minor injuries have forced fights to be postponed. Promoters have also squabbled over where to hold the bouts, causing more delays and uncertainties for an event that was designed to cut through the clutter in what was considered one of the sport's hottest divisions.

"I have been assured that it will heal completely and that I will be back in the ring next year," Kessler said of his injury. "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."

It was not clear what caused the eye injury, although Kessler was cut by an accidental headbutt near the eye during his loss to Ward on Nov. 22. The American star took the WBA title from Kessler in a bout that was stopped early on the advice of ringside physicians.

Promoter Kalle Sauerland said it was "not bad news but it is a bombshell."

Christian Meyer, the managing director of promoters Team Sauerland, said a visit to eye specialist Professor Dr. Med Gerhard Lang in Germany on Tuesday confirmed the injury.

"The doctor confirmed that only a proper rest — so not much of a treatment — simply rest from boxing activity would lead to a full recovery," Meyer said.

Sauerland said he had "a verbal agreement" for a fight next year between the 31-year-old Kessler and the winner of the Super Six, although no date has been considered.

"You can recover from losing in the ring, but you cannot recover from losing your health," Sauerland said. "There is nothing of bigger importance than a boxer's health. As much as we regret to see Mikkel pulling out, he was left with no other choice."


Associated Press Writer Jan M. Olsen in Copenhagen, Denmark, contributed to this report.