The ruling also said an investigation revealed evidence that Gabrielle Schoeneweis' cocaine use "may have caused harm to another person." That person was not identified.
Gabrielle Schoeneweis was found dead on May 20 in the master bedroom of the couple's home in Fountain Hills, a Phoenix suburb.
A three-judge Court of Appeals panel disclosed the cause of death in a ruling on whether an autopsy report and other records on Gabrielle Schoeneweis' death must be disclosed under Arizona's public records law.
The Court of Appeals panel said further proceedings are needed to determine that based on public interest in any investigation into criminal conduct.
But the panel said its ruling disclosed the cause of death to provide guidance "in this and other cases" and because cause of death is a central fact not subject to consideration of whether privacy rights outweigh public interest for disclosure of public records.
An attorney for Schoeneweis argued in a lawsuit filed against state and Maricopa County officials that release of information on the cause of death would cause emotional suffering for the family.
The Court of Appeals panel's ruling came on Schoeneweis' appeal of a July 9 ruling in which a trial judge denied Schoeneweis' request to seal the death certificate and any other documents concerning the cause of death.
The Court of Appeals temporarily barred release of the documents while it considered Schoeneweis' appeal.
Mark Dangerfield, the attorney representing Schoeneweis in the appeal, said it was disappointing that the ruling disclosed the cause of death. He declined to comment further.
Authorities said Gabrielle Schoeneweis' 14-year-old daughter called the sheriff's office to report that she had found her mother lying on the floor and unresponsive.
Schoeneweis and his wife celebrated their 10th anniversary in January. They had three children together, and she already had a daughter when they were married.
Schoeneweis, a left-handed relief pitcher, spent three weeks on the bereavement list after his wife's death before returning to play on June 9. He gave up 15 earned runs in nine innings when he came back and was placed on the disabled list Aug. 11 because of depression. He returned to the team on Sept. 7.
He had signed a one-year contract with Arizona for 2009 and is now a free agent.