Porter Fischer, a former associate of Biogenesis head Tony Bosch, told The Associated Press on Friday that he fears releasing more names and involving more leagues would further complicate his life.
"This whole fiasco with MLB has made me very, very wary about doing this with another agency," Fischer said. "The way this whole thing has gone down with MLB makes me really, really apprehensive about starting another forest fire with somebody else. I mean, if you were me, would you go pick a fight with somebody else? I'd have NBA fans calling me names, I'd have a whole bunch of high-paid athletes calling me this-that, I'd have other goons at my door."
Fischer did not divulge any new names in the AP interview.
Earlier this week, ESPN.com published a story saying Fischer alleged that NBA players, boxers, tennis players, college players and MMA fighters were among those who bought performance-enhancing drugs from Bosch, who operated the clinic.
"This whole thing is so mind blowing to me," Fischer said.
Several MLB players have also been linked in media reports to the clinic, most notably Yankees slugger Alex Rodriguez, 2012 All-Star game MVP Melky Cabrera, 2005 AL Cy Young Award winner Bartolo Colon and 2011 AL championship series MVP Nelson Cruz.
Milwaukee outfielder Ryan Braun, the 2011 National League MVP, agreed this week to a 65-game suspension for violating baseball's rules on drug use after being connected to Biogenesis.
Fischer said he wants law enforcement to take a hard look at what occurred at the clinic, and that his life has been threatened since he gave documents about the clinic and its customers to the Miami New Times, which published a story in January detailing the alleged purchase of performance-enhancing drugs by Rodriguez and others.
"I'd like to give it to the proper entities," Fischer said. "But again, right now, I'm worried about walking out of my own house."