The texts, the source said, usually came late at night, telling Anthony Bosch to come to the house. Bosch would then head to the waterfront mansion on Biscayne Bay, through the gate on North Bay Road, to inject performance-enhancing drugs into Alex Rodriguez.

Procedures were different, though, sources told "Outside the Lines," for the other athletes who were customers of Bosch's Biogenesis of America clinic in Coral Gables, which Major League Baseball considers the center of a widespread doping operation in South Florida. Those athletes, sources said, relied on intermediaries to transport the performance-enhancing drug regimens Bosch provided.

But for A-Rod, the service was always personal: "Only Tony handled A-Rod," one source told "Outside the Lines."

The visits were every few weeks. One night last spring, a source said, Bosch told associates he had been kicked out of Rodriguez' home after he had trouble locating a vein and infuriated the player. The sources did not say why Bosch would have been tapping a vein, as HGH and testosterone do not require intravenous injections. But whatever he was doing, "Tony said A-Rod was pissed at him," a source said. "He said he was bleeding everywhere."

Several sources, speaking on the condition of anonymity, said Bosch spoke openly about his relationship with the Yankee All-Star, and two sources said that documents they reviewed detailed the drug regimens and schedules Rodriguez received.

A spokesperson for Rodriguez on Friday said, "the allegations are not true."

MLB officials say they believe Bosch is the center of the South Florida doping operation and have urged the U.S. Drug Enforcement Agency to open an investigation. But numerous sources contacted by "Outside the Lines" say that they have not been interviewed by federal agents or by MLB investigators, and are not aware of any law enforcement effort to seize material from the now-shuttered Biogenesis office or Bosch's home. MLB officials have turned over information they collected to the DEA. But sources in Florida said they have seen no indication that an investigation has begun. DEA officials have declined to comment on the existence of a case.

Rodriguez was named in the Miami New Times on Monday as one of numerous athletes listed in Biogenesis paperwork. A source told "Outside the Lines" Bosch had an aversion to computerized records and wrote all of his records by hand. The other MLB players named were Melky Cabrera, Bartolo Colon, Nelson Cruz, Yasmani Grandal and Gio Gonzalez.