Kingston, Jun 26 (IANS): The name of Usain Bolt missed from the list of athletes for the Jamaica National Senior Championships on Friday.

The world's fastest man had been scheduled to participate in the national trial when preparing for this August's World Championships in Beijing where he would defend 100 m and 200 m titles, Xinhua news agency reported.

This withdrawal along with lack of form raised concerns over the future career of the six-time Olympic gold medallist.

Bolt has been struggling with relatively poor performance since the start of the season during which his best record was 10.12 seconds for 100m and 20.13 for 200 m.

After last week's New York Diamond League, where Bolt ran a sluggish 20.29 to win 200 m, his coach Glen Mills implied more races are needed by the star sprinter.

"He's going to be running a lot more races in order to get him into competitive peak shape. He hasn't been doing much in terms of competitive running. Over the next two months, you'll see him doing quite a lot more races with a more aggressive approach," Mills said.

However, in response to the last-minute withdrawal, Bolt's manager Ricky Simms told media "Usain was never confirmed to run at the trials" though his name was submitted.

"He put his name in to have the option," Simms explained, adding it was Mills who could make the decision.