Hearings in the cases involving Alberto Salazar and doctor Jeffrey Brown are unlikely to be held before March, the Court of Arbitration for Sport (CAS) announced after confirming they had appealed their respective four-year bans.
In a statement, the CAS said it had registered the appeals filed by the two officials, who were sanctioned following an extensive investigation by the United States Anti-Doping Agency (USADA).
The hearings are not set to take place until March at the earliest after both "requested additional time to file their written submissions and evidence", the CAS added.
Salazar was banned for "orchestrating and facilitating prohibited doping conduct" as head coach of the Nike Oregon Project (NOP), a camp designed primarily to develop US endurance athletes.
USADA alleged Salazar trafficked banned performance-enhancing substance testosterone to multiple athletes.
Salazar was also said to have tampered, or attempted to tamper, with NOP athletes' doping control process, according to USADA.
He denies wrongdoing.
Brown, a paid consultant endocrinologist for NOP on performance enhancement and who served as a physician for numerous athletes in the training programme, was also banned for four years.
No athletes have been charged with any offences, although the World Anti-Doping Agency (WADA) has promised to investigate those coached by Salazar.
It came after the International Olympic Committee called on WADA to look into those associated with the 61-year-old American.
Britain's four-time Olympic gold medallist Sir Mo Farah and double world champion Sifan Hassan of the Netherlands are among those to have been coached by Salazar.
Neither has been charged with a doping offence and both deny any use of prohibited substances.
The NOP has been shut down following Salazar's ban, while Nike’s long-time chief executive Mark Parker announced last month that he was leaving the position in January.