Other athletes linked to the investigation by news sources include Ankiel, Harrison, Toronto Blue Jays third baseman Troy Glaus, former Orioles outfielder Gary Matthews Jr., former Orioles second baseman Jerry Hairston Jr. and at least 11 professional wrestlers.
As the steroid cloud began to loom over baseball, fans associated possible use with sluggers who had bulked up mid-career. But Gibbons, Ankiel and Glaus are linked more by long histories of injuries.
Gibbons missed 65 games because of injuries during the 2004 season, when he allegedly bought testosterone and growth hormone. Glaus missed large portions of the 2003 and 2004 seasons because of a shoulder injury. His alleged steroid purchases fell between September 2003 and May 2004, according to SI.com. Ankiel, responding to a report in the New York Daily News, said he received a medical prescription for hGH to help him recover from reconstructive elbow surgery in 2004.
"The connection I see between these guys is desperation," Carroll said. "Whether it's desperation to recover from an injury or desperation to earn a contract, the risk becomes worth it."
hGH and injuriesUsers of hGH anecdotally report increased energy and ability to perform rehabilitation exercises in the wake of injury.
"It reduces inflammation and gets rid of the pain," Segui said. "But there's a misconception that it's about bulking up like what you see in the muscle magazines."
Some doctors believe hGH helps with recuperation.
"I'm not sure the research is in place," Wadler said, "but the general sense among people who deal with these issues is that it can be a reasonably effective recovery tool."
But not all agree. Vance said she prescribes hGH to patients with malfunctioning pituitary glands and to children whose bodies produce too little growth hormone naturally. Those, along with the treatment of frail AIDS patients, are the only legitimate uses for the substance, Vance said.
Researchers agree on the difficulty of detecting hGH. Growth hormone doesn't show up in the urine tests used by American professional sports leagues. Even in a blood test, synthetic hormone looks similar to the hormone produced naturally by the body. And none of the major sports unions has agreed to blood testing.
If enforcement officials dwell on hGH, however, they're missing the point, said Carroll, who said he believes athletes have moved on to a new generation of performance-enhancing drugs, such as insulin.
"It was the wonder drug a few years ago, and guys were flocking to it," he said of hGH. "But now it's almost beside the point. We don't learn what the state of the art is from the scientists. We learn from the users."
Sun reporter Roch Kubatko contributed to this article.