Australian record holder Alex Rowe has withdrawn from the 800m at next month's world athletics championships in Beijing, citing a lack of form.
Rowe, 23, burst to prominence in 2014 when he equalled Olympic champion Ralph Doubell's 46-year national record of 1 minute, 44.40 seconds in Monte Carlo.
But having commenced post-graduate studies in medicine this year, he has been unable to recapture that form.
"My recent race results have made it clear that I am not in the shape expected of an international athlete and consequently it was evident that this was the best decision," said Rowe.
"In February of this year I commenced my post-graduate studies in medicine and some of the challenges faced since, including living out of home for the first time, training independently and balancing my preparation with study, has been very difficult.
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"My recent race results have been extremely disappointing and when considering the short time-frame between now and the start of the championships I am unlikely to turn my season around."
Rowe made the decision to pull out of the August 22-30 world titles in consultation with his coach Justin Rinaldi and family members.
He will defer his university studies in 2016 to give him the best possible chance of excelling at the Rio Olympics.
Australian head coach Craig Hilliard supported the difficult call made by Rowe.
"This decision is the right one for Alex and that is what is most important as we build towards Rio," said Hilliard.
"I am confident that he will complete his study shortly, before knuckling down to achieve the performance goals we know he is capable of."
Rowe's withdrawal means in-form Jeff Riseley will be left to fly the Australian flag in the men's 800m in Beijing.
Riseley clocked 1:44.99, his fastest time in three years, at a meet in Italy earlier this month.
The long-striding Victorian will take excellent form into the world titles having become the first man in 24 years to do the 800m/1500m double at the national championships - a feat he achieved in March.
The selection cut-off for the world titles is August 9.
