Former NFL player Mike Williams died from a rare form of sepsis related to dental health problems, according to a medical examiner’s report released Friday.

Williams, 36, died Sept. 12 after being hospitalized following a construction accident while working as an electrician.

The wide receiver played four seasons with the Tampa Bay Buccaneers after he was drafted out of Syracuse in 2010. His best season was as a rookie when he led the team with 11 touchdowns and had 964 receiving yards. He also played for the Buffalo Bills and was on the Kansas City Chiefs’ roster before leaving the NFL in 2016.

The Hillsborough County Medical Examiner’s report says the cause of Williams’ death was bacterial sepsis traced to a dental infection and “retained tooth roots.” The report is preliminary. A full autopsy will be released later and include toxicology and other information, officials said Friday.

The initial report also cites cardiovascular disease as a contributing factor in his death, which is listed as natural.

This is the first time in Hillsborough County that a death has been attributed to this specific type of dental sepsis, according to the medical examiner’s office.