Calls are mounting for Russia to be banned from the Rio Olympics entirely after a damning report into systematic doping at the 2014 Sochi Winter Olympics.
Such wholesale Russian absence would cause significant changes in the medals table, with Russia having claimed 79 medals - including 22 golds - four years ago in London.
Apart from its track and field stars, who are already coming to terms with a ban, we pick out five more Russian contenders who might miss out.
1. Sofiya Velikaya (fencing)
Having surprisingly missed out on women's sabre gold in London, Velikaya took some time out of the sport before returning to clinch double gold at the 2015 World Championships. She would start the competition in Rio as the athlete to beat.
2. Russian synchronised swimming team
Women's team and duet competitions have been held since the 2000 Sydney Olympics - and Russian athletes have swept all eight gold medals. It is almost inconceivable that, assuming they are allowed to compete, they would not do the same again.
3. Yana Kudryavtseva (rhythmic gymnastics)
Winner of no fewer than 15 world titles since 2013, the 18-year-old Kudryavtseva - who was still a junior in 2012 and did not compete - is the unbackable favourite to win the women's all-around title in Rio, as well as leading her nation to the team prize.
4. Vitaly Dunaytsev (boxing)
Any Russian boxer who fights his way through their brutal selection process is bound to be special, but there are signs that light-welterweight Dunaytsev - who won both world and European titles in 2015 - could be the best of the lot.
5. Tagir Khaybulaev (judo)
Russia topped the judo medals table in 2012 with three golds. One of those victors, men's 100kg competitor Tagir Khaibulayev, will return in search of his second consecutive gold medal - provided he is cleared to take part.