Skaggs, who was a member of the Los Angeles Angels at the time of his death, died July 1 due to a combination of fentanyl, ethanol and oxycodone found in his system.
Skaggs was 27 years old.
ESPN's T.J. Quinn reported the DEA often becomes involved in cases involving fentanyl in an attempt to learn about how the drug was obtained.
"One federal law enforcement agent, speaking on condition of anonymity, said fentanyl has been showing up 'everywhere, even in marijuana,'" Quinn reported.
Skaggs' family has said that the use of drugs and alcohol was "out of character" for the pitcher. The family has hired a Texas attorney to investigate Skaggs' death.
This story was originally published by Shane Dale on KNXV in Phoenix.