The autopsy detected an abnormality in Pontiff's heart, according to Treuting. Further tests are being conducted to determine the exact cause of death and results may not be known for several days.
"All toxicology studies were negative," Treuting said. "Specifically, there were no illegal drugs, nor any prescription or over-the-counter drugs in his system."
The heat abnormality may not be linked to the cause of death by natural causes, said Janie Badinger of the Jefferson Coroner's Office.
Pontiff, an All-Southeastern Conference pick the last two seasons, was found dead in his bedroom at his parents' home in Metairie last Wednesday. He was a 21st-round draft pick of the Oakland Athletics but had not yet decided whether he wanted to accept a pro contract or play his senior season at LSU.