Over 100 Russian athletes are set to fly out to Brazil Thursday, with at least half of them in the dark regarding their status at the start of the day. By 4.15pm GMT on Wednesday, 19 Russians were still nervously waiting clearance for the Games.
Russian president Vladimir Putin met with the delegation of athletes at the Kremlin Wednesday, though it was not clear whether the group included some who had been disqualified.
At least 104 Russians have been banned from attending the Olympics.
Among the 67 banned track and field athletes are two-time Olympic champion pole vaulter Yelena Isinbayeva, and defending high jump gold medalist Ivan Ukhov. In London 2012, track and field was Russia's most successful sport, yielding 16 medals, including seven golds.
Also barred from traveling to Rio are 22 rowers, seven swimmers, five canoeists, one pentathlete, one volleyball player and one sailor.
Tennis pro Maria Sharapova, who waved the Russian flag at the Opening Ceremony of London 2012, is already serving a two-year ban imposed by the International Tennis Federation (ITF) for a positive drug test.
"I think that in Russia, and in other countries, we need to create an education system in children sports schools which would be in the genes of athletes" the head of the Russian Tennis Federation Shamil Tarpischev told CNN.
"Unfortunately there is not enough of a sporting culture at the moment so that sportsmen understand the significance of these negative occurrences."
All Russian Olympians participating in archery, shooting, fencing, equestrian, triathlon and judo have been given the go-ahead by their respective federations, according to graphiq.com
which compiles its data from information provided by the Associated Press. The International Judo Federation -- which cleared all 11 Russian participants -- is chaired by honorary president Putin
Russia's defending men's gold medal volleyball team will be without Alexander Markin, who had previously tested positive for a banned substance (meldonium, the same drug taken by Sharapova), earning him an automatic disqualification given the IOC's strict stance following accusations levied against the Russians in the past year.
Of greater importance to Russia, however, was the clearance on Wednesday of all 20 gymnasts (defending 12 medals), 17 wrestlers (defending 11 medals) and 11 boxers (defending six medals).
Russian Olympic Committee chairman Aleksandr Zhukov expects a final decision to be made on all his athletes by Thursday, according to the state-run TASS news agency. Earlier this week, Zhukov announced the formation of a national anti-doping body
Slots open up for other federations
With the fate of a few athletes still unknown, those who were just short of qualifying for Rio in their sports have been clutching renewed hope. Case in point: Australia's women's eight rowers, previously the first reserves, found out on Wednesday that they would qualify following the ban on their Russian counterparts.
Australia's Olympic team chief Kitty Chiller celebrated the news, despite the short notice. "Obviously to learn today and jump on a plane in a few days is probably not ideal," Chiller told the Guardian. "I'm not sure what they've been training like in the last couple of weeks, but I'm sure adrenaline and the emotion will overtake all of that."
Chiller added that the move indicated that governing bodies in sports were "starting to pounce" on drug cheats.
Still awaiting decisions
Still awaiting their fate at the time of writing are three taekwondo fighters, three table tennis players, eight weightlifters, four badminton players and one golfer.
The necessity of clearances from individual sports authorities came after the IOC refused to ban the entire Russian Olympic team, despite outcries from the international sporting community to do so after the World Anti-Doping Agency (WADA) confirmed it found evidence of state-sponsored doping.
The WADA investigation was spurred by claims made by former Russian anti-doping laboratory director Grigory Rodchenkov last year to the New York Times that he was ordered to cover up the drug use of at least 15 Sochi 2014 medal winners.
The Russian track and field team had already been barred from competing in Rio by the sport's governing body, the IAAF. Just one of the 68 athletes who qualified for the games appealed successfully. That's long jumper Darya Klishina, who having trained in the U.S. was granted a reprieve by the IAAF earlier this month.
In his statement, whistleblower Rodchenkov alleged that he assisted in doctoring urine samples provided by Russian athletes during overnight shifts at the Sochi Games. He also accused the Russian secret service of providing active assistance with the cover-up, which he says took place before, during and after the Sochi Olympics.
Rodchenkov's statement followed allegations from another former employee of the Russia Anti-Doping agency, Vitaliy Stepanova, who claimed in a German documentary that the Russian Olympic federation supplied banned substances to athletes in exchange for 5% of their earnings. Stepanov is married to former Russian middle-distance runner Yuliya Stepanova, who backed up the claims.
"In a training camp in Portugal, our athletes simply lived under false names," said Stepanova, "They have taken banned substances, they undertook a course of doping, and to ensure that foreign control officers did not come and test them, they provided false names."
Stepanova relocated to the U.S. and was given permission to compete as a "neutral athlete" in any international competition, as long as she had received a invitation from the competition organizer. However the IOC decided not to give Stepanova a competition invite to Rio.
Unlike U.S.-based long jumper Klishina, Stepanova had previously tested positive for banned substances, which appeared to override any goodwill for going public with the claims.
The couple are currently contesting the IOC's decision -- which coincided with an invite to watch the games as spectators -- responding with an open letter to IOC Director General Christophe de Kepper.
"We never blew the whistle with the intent to getting a spectators' invitation to Rio," the couple said in the letter. "We have not asked for a favor, we have asked for a fair and ethical treatment."
Doping allegations have repeatedly been discredited by Russian authorities, including a spokesman for President Vladimir Putin who has previously referred to Yuliya Stepanova as "Judas."
A documentary alleging that Russia has fallen victim to an international smear campaign was scheduled to air last week on Russian television.
The 25-minute film titled "The Doping Trap" profiles four Russian athletes along with drug testing supervisors who counter the claims of Stepanova and Rodchenkov, while alleging they have been victims of an elaborate set-up.
CNN's Clare Sebastian contributed reporting to this story.