The players' union says it has been assured no decisions regarding discipline will be made until the interviews are completed.
"It would be unfortunate if anyone prejudged those investigations," union head Michael Weiner said in a statement Wednesday.
And it appears the process has a while to run.
Interviews with players started three weeks ago and are scheduled until the end of June, according to people with knowledge of the process who spoke on condition of anonymity because statements on those details weren't authorized. Dan Halem, Steven Gonzalez and Patrick Houlihan, lawyers in baseball's labor relations department, conducted several interviews, and some players haven't been scheduled.
"Every player has been or will be represented by an attorney from the players' association," Weiner said. "The players' association has every interest in both defending the rights of players and in defending the integrity of our joint [drug] program. We trust that the commissioner's office shares these interests."
MLB has been seeking the cooperation of Biogenesis founder Anthony Bosch since Miami New Times reported in January that it obtained what the paper said were records detailing drug purchases by Rodriguez, Cabrera, Cruz and Colon. Yahoo Sports reported that Braun, the 2011 NL MVP, was mentioned in the records.
MLB sued Biogenesis and its operators in a Florida court in March, an attempt to pressure Bosch. A person familiar with the case told The Associated Press on Tuesday night that Bosch agreed to talk to MLB, a deal first reported by ESPN. MLB wants to speak with Bosch in the next few days,
"Due to ongoing litigation, it would be inappropriate to comment on any aspect of this matter at this time," Bosch's lawyer, Susy Ribero-Ayala, said in a statement.
Among the players linked to the clinic, Cabrera, Colon and San Diego catcher Yasmani Grandal already have served 50-game suspensions following positive tests for testosterone announced by MLB last year.
"It looks like it could be getting to the bottom of this and finding some information that hopefully would help Major League Baseball as far as cleaning this game up," said San Francisco manager Bruce Bochy, who managed Cabrera last year. "I always thought they should be a little stricter to keep these players from trying to beat the system and cheat. I'm all for stiffer penalties."
Once MLB interviews Bosch and the players, it will have to determine what penalties to impose.
"WADA commends the decision of Major League Baseball to seek suspension of an estimated 20 players," World Anti-Doping Agency director General David Howman said in a statement.
"More and more, information and evidence gathered in the investigative process is proving an effective means of uncovering doping in sport. MLB has approached this issue in a professional way, and the evidence gathered will undoubtedly be pivotal," Howman said.
Any suspensions for first offenders would be put on hold if the union files a grievance, a process that would put the matter in front of an arbitrator and delay possible sanctions for weeks or months. Second offenders would serve suspensions during the grievance process.