Horse Sport Ireland announced the decision yesterday, following discussions between show jumping Team Manager Robert Splaine and Hanley. The rider asked for permission to avoid competing as part of the Irish team at the Nations' Cup at Aachen next week because of "distracting issues which have emerged" since the Balve international show, where he was competing as an individual two weeks ago.
Hanley, 36, asked to be excused from the team as he was concerned that the issues could impact on the performance of the Irish team.
RTE Sport reported on Friday that Hanley was under investigation by the German equestrian federation. It is alleged a syringe was found in the pocket of a jacket belonging to the Irish rider at the German Equestrian Championships at Balve on the weekend of June 13, according to the federation's secretary-general Soenke Lauterbach, who spoke to RTE.
"I just happened to be nearby when the jacket was picked up," Lauterbach said. "We looked in the pockets to try and find out who might be the owner, and then we found a used syringe," he told RTE.
Tests have been ordered on Hanley's three horses and samples have been sent to the FEI.
Team Manager Robert Splaine hopes to announce a replacement for Cameron Hanley on the Aachen team shortly.