The World Anti-Doping Agency (WADA) has agreed to dismiss all but one of the first 96 Russian doping cases forwarded by sports federations.
The cases stem from Richard McLaren's investigation, detailing evidence of a scheme to hide positive doping tests at the Sochi Winter Olympics and beforehand.
The 95 dismissed cases were described by WADA officials as not containing enough hard evidence to result in a solid case.
"It's absolutely in line with the process and, frankly, it's nothing unexpected," WADA director general Olivier Niggli told AP on Wednesday at International Olympic Committee (IOC) meetings in Peru.
"The first ones were the quickest to be dealt with, because they're the ones with the least evidence."
McLaren uncovered 1000 potential cases. A WADA spokesperson told AP the agency understood sports federations were considering bringing some of them forward. There are at least 900 more cases being pursued.
Niggli cautioned that it would be difficult to pursue some cases, because the Russian scheme involved disposing of tainted samples, and the Russians were not cooperative in turning over evidence.
"There are a thousand names and, for a number of them, the only thing McLaren's got is a name on a list," Niggli said. "If you can prosecute an athlete with a name on a list, perfect. But this is not the reality. There were thousands of samples destroyed in Moscow."
The revelation of the 95 dropped cases comes with a deadline fast approaching for a decision on Russia's participation at February's Winter Olympics.
Two IOC committees will decide the matter: one reviewing individual cases and another looking at overall corruption in Russia. They are due to deliver interim reports later this week at the IOC meetings.
In resolving the case against Russia's suspended anti-doping agency (RUSADA), WADA has insisted the agency, the country's Olympic committee and its sports ministry "publicly accept the outcomes of the McLaren Investigation". Track's governing body imposed similar conditions to lift the track team's suspension.
The IOC, however, has made no such move. More than 270 Russian athletes were cleared to compete in the Rio Summer Games.
"The best we can do to protect clean athletes is to have a really good, solid anti-doping process in Russia," said WADA president Craig Reedie, also a member of the IOC. "That's our role and our priority. The rest of it, you have to go and ask the IOC."
Russian officials are showing no signs of acknowledging they had run a state-sponsored doping program.
This week, deputy prime minister Vitaly Mutko blamed RUSADA and Russian anti-doping lab former head Grigory Rodchenkov for the corruption, and suggested WADA was at fault, too. Rodchenkov lives in hiding in the United States after revealing details of the plot.
