By Michael Hann
(Reuters) - Usain Bolt's lack of form combined with his late withdrawal from the Jamaican 100 metres national trials on Thursday have raised more doubts about the future of the world's fastest man.
The towering sprinter had intended to run in the trials as a sharpener but the Jamaican Athletics Administrative Association confirmed he had pulled, out two months before the world championships in Beijing.
Six-times Olympic gold medallist, Bolt, who qualifies for world championships as defending champion in both events, has struggled this year with moderate best times of 10.12 seconds for the 100 and 20.13 in the 200.
The 28-year-old expressed uncharacteristic concerns after a sluggish 20.29 to win the 200 at the recent New York Diamond League meeting.
"I'm not happy about my performance. My turn was horrible, I don't know what happened," Bolt said. "My worst turn ever."
"After I came off the turn, I knew it wasn't going to be fast... so I pretty much just wanted to get home."
Bolt's 2014 season was limited by injuries but he was the star attraction at the Commonwealth Games in Glasgow, winning gold in the 4x100 relay.
With 2015 continuing in a similar vein, Bolt, the only man to win the 100 and 200 in back-to-back Olympics, would surely have wanted to lay down a marker at the Jamaican trials following the resurgence of Justin Gatlin.
Controversial United States sprinter Gatlin, who has served two doping bans, has become the man to beat after setting or equalling lifetime bests in both the 100 and 200 this year.
Gatlin has not raced Bolt since 2013, but the 33-year-old 2004 Olympic gold medallist is hoping his rival returns to his best at the world championships so he can dethrone the Jamaican in Beijing.
"What is it really going to amount to if I go out there and run against Usain when he is not at his best," Gatlin told Reuters.
"That is not a great storyline. It is not a race I would like to go out and win. I want Usain at his best, and I think he wants me at my best. That's what people want to see."