MLB commissioner Rob Manfred said that he advises Hall of Fame voters to refrain from surmising that candidates used performance-enhancing drugs without "credible evidence," according to ESPN.com.
Mike Piazza and Jeff Bagwell are among the players whose Hall of Fame cases are believed to have been damaged by the suspicion of PED use.
Manfred, who took over for Bud Selig on Jan. 25, said voters should try to distinguish between players who were disciplined after testing positive and others linked to PED use.
Asked what he would tell the Hall of Fame about how it should handle the PED era, Manfred replied: "The only piece of advice that I'm comfortable giving is that I think that everyone should keep in mind the difference between players who tested positive and were disciplined on the one hand, and players where somebody has surmised that they did something on the other. And I think, based on what you read in the media, sometimes those lines get blurred. And I think it gets really important to keep that distinction in mind.
"I think it's unfair," Manfred said, in answer to a follow-up question, "for people to surmise that Player A did X, Y or Z, absent a positive test, or proof that we produced in an investigation, or whatever. I just think it runs contrary to a very fundamental notion in our society, that you're innocent until somebody proves you're guilty."
Manfred did not say whether he feels there is proof that Barry Bonds used PEDs, but said he thought the Mitchell Report "produced evidence of use." The report also included 82 mentions of pitcher Roger Clemens.
Both players have received low percentages of votes during their time on the ballot.