Blake (right) and 100m world record holder Usain Bolt are training partners
Five Jamaican athletes set to compete at the World Championships after being cleared of doping offences have now been pulled out of the event.
Relay runners Yohan Blake, Allodin Fothergill, Lansford Spence, Marvin Anderson and Sheri-Ann Brooks were withdrawn by their own team.
They tested positive for methylxanthine at Jamaica's championships in June.
But they were cleared by a disciplinary panel on the basis it was not on the World Anti-Doping Agency banned list.
The Jamaican Anti-Doping Commission (Jadco), which set up the panel, then appealed against the verdict passed by athletics' governing body IAAF, stating the substance had a similar structure to tuaminoheptane, a banned stimulant according to Wada.
"Jamaica will not enter these athletes," IAAF spokesman Nick Davies said.
"The news I have is that they will not be running."
Jamaica had said a final ruling on the matter would be taken after the championships prompting the IAAF to allow them to run as they had been cleared even though the appeal was pending.
However, the ruling body warned that if Jamaica subsequently banned the athletes for doping, their results in the relays would be void and any medals won would be taken away.
All five runners were part of the Caribbean nation's 46-strong team.
Blake, who won bronze in the 100m at the world junior championships in 2006, is Olympic champion Bolt's training partner and has recorded the fifth-fastest time over 100m this year.
Anderson is also a 100m runner, while Fothergill and Spence compete in the 400m.
Brooks, the Commonwealth 100m champion, was cleared last week on a technicality because Jadco tested her B sample without her knowledge.
BBC Sport travelled to Jamaica to find out how such a small country has been able to consistently produce, develop and nurture world-class athletes