MLB officials asked federal drug agents for help, the newspaper reported Sunday, quoting two sources.
Many baseball players who recently flunked drug tests live or train southern Florida or travel there for treatment, the sources said.
MLB sent investigators to South Florida to determine the source of drugs and passed the information gathered to the U.S. Drug Enforcement Administration because the league does not have subpoena powers, the report said.
Numerous wellness and anti-aging clinics are in the region. Anti-aging treatments include testosterone and human growth treatment, two types of performance-enhancing drugs.
Baseball officials believe an organized ring could be involved in distributing testosterone or other steroidal drugs to players, the report said.
It wasn't clear how far the DEA is into the investigation. A spokesman for the agency's Miami field office declined to comment.