Investigators are probing the possibility that Dr. Pedro Publio Bosch, 71, supplied Ramirez with a prescription for human chorionic gonadotropin, a female fertility drug used by athletes to restore hormone levels after a steroid cycle. The drug is banned by Major League Baseball.
Agents are also looking into whether Bosch's son, 45-year-old Andrew Bosch, was a middle man between Ramirez and his father.
Neither Bosch commented on the report to the Herald.
MLB referred the matter to the DEA, though no criminal case has been opened. DEA officials wouldn't confirm any investigation to the Herald.
Ramirez is the highest-profile player suspended under baseball's drug policy, implemented in 2003 after a wave of congressional pressure. Before the 2009 season started, New York Yankees third baseman Alex Rodriguez admitted using steroids between 2001 and 2003 after Sports Illustrated reported he failed a survey test in 2003.
Rodriguez wasn't suspended, however, because the failed test preceded the implementation of punishments.