Asafa Powell believes his chances at the London Olympics could have been at risk had he have competed in the 100m at the World Championships.
The 28-year-old Jamaican pulled out of the Daegu event with a groin injury initially suffered in the Diamond League in Birmingham last month.
And he said: "It's a very strong field so I can't go out there with pain and finish way back in the field and maybe not be able to be back for next year.
"I just couldn't risk that."
Powell's injury forced him to , and he aggravated it when he returned to training ahead of Daegu.
"I'm very down right now because I've trained 11 months for this and to come here and not be able to compete, I feel very disturbed about it," Powell added.
"It was my plan to come here to win, to beat the entire field and I'm not able to do it. But definitely I had a great chance of winning.
"I'm very frustrated but over the years I've been injured and I keep going and keep going and this won't stop me. I'll just work my way back for next year.
"I'm motivated to really come back and just prove to the world I definitely can run fast and run fast under pressure."
Asked if he felt it was fate he would never win an individual global gold medal, he said: "Honestly, yes. I think about that a lot.
"Every time it comes to the big one there is always something that prevents me from getting it. But it's just life and I have to live with it and just hope for the best.
"I'll feel disappointed if I don't finish my career with a global title but I'll retire as one of the best sprinters that has ever touched the track and that's still something to be happy about."
Despite the injury, Powell's agent Paul Doyle told the BBC the sprinter could still be fit for the 4x100m relay on 4 September.
Powell clocked the fastest 100m time in the world this year - 9.78 seconds - at the Diamond League meeting in Lausanne in June.
And his absence almost gives compatriot Usain Bolt a free run at both the 100m and 200m titles - races he scored world records in two years ago in Berlin.
Olympic champion Bolt told the BBC: "It's really sad. I can't imagine how [Asafa] is feeling that he's not able to compete after doing so well throughout the season.
"I was looking forward to it - it was going to be a showdown."
Asked if the race had lost something, Bolt said: "A lot of people are going to look at it like that but I can't because there are going to be seven other guys besides me.
"They haven't come out here to say, 'Usain's the fastest man in the world, let's give him a gold medal'. They've come to win so I'm really focused and I'm ready."
France's European 100m and 200m champion Christophe Lamaitre added: "Of course, it's very sad for Powell but I think it's a good opportunity for the rest of the sprinters."
The news also increases the chances of British sprinter Dwain Chambers making the final.
The 100m heats begin on Saturday in South Korea, with the final at 1245 BST on Sunday, while the 200m starts on Thursday 1 September.