Paralympic cycling champion Michael Gallagher has been suspended after testing positive for banned substance EPO, ruling him out of the Rio Games.
The Scotland-born Australian won track golds in Beijing 2008 and London 2012.
The Australian Sports Anti-Doping Authority (Asada) said he would not be allowed to compete in Rio while it investigates.
It said the 37-year-old failed an out-of-competition test at a training camp in July.
The Paralympic Games start on Wednesday, 7 September.