The NRL has also confirmed around 10 former players will also be interviewed.
ASADA will begin the interviews next week, and the process is expected to take four to six weeks.
Essendon is also under ASADA investigation over the possible use of banned substances last season.
It has also been revealed that apart from the well-documented issues at NRL club Cronulla, no other club was suspected of systematic doping.
The focus was now on players, or groups of players, who may have acted outside of their club programs.
The NRL won't stand down any of its players until there is sufficient evidence, and the code expects co-operation from those ASADA wishes to speak to.
"If interviews don't take place there are very clear procedures for us to follow up with individuals within the code of conduct, which is exactly what we will do," NRL chief executive Dave Smith said on Wednesday.
"I don't expect that to be the case.
"ASADA will tell us the players they want to us to contact and through our integrity unit we will issue the notices."
Essendon had no comment on the latest developments.
