Olympic all-around champion Paul Hamm, winner of one of the most controversial golds in 2004, withdrew from the Beijing Games on Monday due to injury.

"I have put my heart and soul into this comeback and I've done everything I could to get ready in time to compete in Beijing," the American told reporters in a teleconference.

"Had I had another month, I think I would have been able to get the job done... I'm dealing with a beat-up body right now."

Hamm was recovering from a broken bone in his right hand sustained in competition on May 22.

But the 25-year-old said he had also since strained the rotator cuff in his left shoulder and has not been able to perform a full routine in over two months.

"For my comeback to be successful I needed to make continuous progress and have no setbacks," he said. "Right now there are only five days of training left before the podium training in Beijing and I can see now that it would be impossible for me to be ready.

"This has been the hardest decision that I've ever had to make but I have too much respect for the Olympics and my team to continue on when I know the best thing for everyone is for me to step aside."

Four years ago Hamm became the first American man to win the all-around title, but his victory sparked one of the biggest controversies of the Games.

He had to battle all the way to the Court of Arbitration for Sport (CAS) to keep his medal after the governing body in gymnastics (FIG) announced he had been handed the gold in error.

The FIG admitted bronze medalist Yang Tae-young should have been awarded the gold as he had been incorrectly docked a 10th of a point from his parallel bars routine but the governing body refused to redistribute the medals.

The FIG's stand forced the South Koreans to appeal against the decision but CAS ruled in favor of Hamm.

After taking a 2-1/2 year break, Hamm returned to competitive action in 2007 and was expected to duel with China's Yang Wei for the all-around title in Beijing.

"It's disappointing because everything was going so well with my comeback after the break that I had for a couple of years," he said. "I pushed for the comeback. I did everything I possibly could. There just wasn't enough time."

Hamm, who in 2003 became the first American man to win the all-around title at the World Championships, said he was ready to leave the sport.

"The truth of the matter is that I've had a wonderful career," he said. "The success I've had in the sport is more than I've ever dreamed of. I'm more than happy with the way things have turned out.

"I had made the decision previous to everything that's gone on in recent weeks that I would be retiring after this Olympics and that's what I plan to do."

No decision had been made on a replacement for Hamm, said USA Gymnastics president Steve Penny. Hamm's twin brother, Morgan, is also a member of the team.

"Enough cannot be said about the effort Paul had made over the last few months and the contribution he had already made to our men's program as we prepare for Beijing," said Penny.

"His decision is being made with the team's best interest in mind. It's a shame this is happening right now," he added.