LOS ANGELES – www.sports.yahoo.com- A source close to Manny Ramirez said Thursday that the illegal substance for which the Los Angeles Dodgers slugger tested positive was not “an agent customarily used for performance enhancing.”

At least not on the baseball diamond. The source, who spoke on condition of anonymity, said the drug was prescribed to address Ramirez’s erectile dysfunction.

However, two sources said the substance Ramirez tested positive for a gonadotropin. Major League baseball’s list of banned substances includes the gonadotropins LH and HCG, which are most commonly used by women as fertility drugs. They also can be used to trigger testosterone production. Testosterone is depleted by steroid use, and low testosterone can cause erectile dysfunction.

“Testosterone and similar drugs are effective for erectile dysfunction in that they jazz up your sex drive,” said Charles Yesalis, a professor at Penn State who has testified before Congress on issues of performance-enhancing drugs. “But far more clinicians accept that affect with Viagra and Cialis. It’s hard for me to understand if it was erectile dysfunction why they would use it.”

Ramirez tested positive for the substance during spring training, then had the urine – a “B” sample – tested again more recently, and it also was positive. Major League Baseball notified Ramirez of the second positive test after Wednesday night’s Dodgers victory over the Washington Nationals. Ramirez admitted to having taken the substance and declined to appeal. His 50-game suspension begins today.

“The substance is not a steroid and it is not human-growth hormone,” the source said.

Ramirez, the source said, acquired the substance through a prescription from a doctor in Miami for his medical condition. The source intimated that Ramirez might bring legal action against the physician.

Ramirez released the following statement Thursday morning: “Recently I saw a physician for a personal health issue. He gave me a medication, not a steroid, which he thought was okay to give me. Unfortunately, the medication was banned under our drug policy. Under the policy that mistake is now my responsibility. I have been advised not to say anything more for now. I do want to say one other thing; I’ve taken and passed about 15 drug tests over the past five seasons.

The Dodgers, who have won a Major League record 13 consecutive home games to start the season, will be without Ramirez until July 3. Outfielder Xavier Paul was promoted from triple-A to take Ramirez’s place on the roster. The suspension will cost Ramirez close to $8 million in lost wages.

Drugs or hormones that increase testosterone production often show up on banned lists.