The IOC is due to make an announcement on Thursday on which Russians have been approved to compete at the Games, having informed the International Federations on Wednesday night of the IOC panel’s decision.
The late confirmation will enable sports such as boxing, diving and tennis to hold the scheduled draws for their competitions.
Three senior IOC members - Germany’s Claudia Bokel, Ugur Erdener of Turkey and Spain’s Juan Antonio Samaranch Jr - have vetted more than 250 Russian athletes declared eligible by the international federations and a Court of Arbitration for Sport expert.
While most of the focus has been on a main group of international federation-approved Russians, many of whom have been in the Olympic Village for the last few days, there is still a small group who are appealing against their bans at CAS.
Swimmers such as four-time world champion Yulia Efimova and rising star Daria Ustinova are still waiting for their cases to be heard, with more than a dozen other cases involving athletes from canoeing, rowing, swimming, weightlifting and wrestling.
Those who win their appeals - and many legal experts think all those barred from competing here because of previous doping convictions have strong cases - could be added to the Russian delegation even after Thursday’s announcement.