Victor Conte, the founder of BALCO who spent time in prison for distributing steroids, is certain that Melky Cabrera is far from alone in using performance-enhancing drugs.

"I'm not going to name names," Conte said in an interview with USA Today, "but I've talked to a lot of top players in Major League Baseball, and they tell me this is what they're doing. There is rampant use of synthetic testosterone in Major League Baseball."

Cabrera, the San Francisco Giants outfielder, was suspended 50 games Wednesday after testing positive for testosterone. Cabrera's suspension is the first of a high-profile player since Ryan Braun, last season's National League MVP, had his suspension overturned by an arbitrator last winter.

Conte was asked by USA Today to make an educated guess as to how many players in baseball are using PEDs.

"I would say," Conte said, according to the newspaper, "maybe as much as half of baseball."

Major League Baseball isn't putting much stock in Conte's estimate.

"There is no way that Victor Conte would have information that would allow him to have any basis on that," MLB vice president Rob Manfred said, according to USA Today. "He's just making that up. It's a guess.