Butko was part of Russia's gold medal-winning side from the London 2012 Olympic Games and was Moroz's team-mate in 2014 for domestic outfit Lokomotiv Novosibirsk.

The pair have been accused of taking unnamed banned substances back in 2014 after allegedly testing positive at the time and they are not due to appeal the case.

"They did not admit their guilt, there is such a procedure for voluntary suspension," said Russian Volleyball Federation secretary general Aleksandr Yaremenko, as reported by Russian state-run news agency TASS.

"By this, the athlete declares that he is not going to challenge the decision of the World Anti-Doping Agency (WADA), but indirectly admits that there was a violation, but not through his fault, but through negligence, or out of ignorance.

"Roughly speaking this is such a deal between the athletes and the commission.

"Accordingly, the athletes are waiting for a softer decision."

Moroz, who played for the national team 22 times from 2012 to 2015, had previously served an 18-month suspension from November 12 2018 after failing a test for cocaine.

As well as his Olympic success, Butko also won the 2011 Men's Volleyball World Cup and 2017 European Championship gold medals with Russia.

The 36-year-old is also a four-time Champions League winner with Lokomotiv Novosibirsk and Zenit Kazan.

"The FIVB will not comment on specific anti-doping proceedings until a final decision on each case is made public," an FIVB spokesperson told insidethegames.

"However, it is important to reiterate that the FIVB maintains a zero-tolerance approach to doping and is 100 per cent committed to protecting clean athletes."

insidethegames has also contacted WADA for comment.