Sean Burroughs -- the ninth-overall pick in the 1998 MLB Draft -- died from a fentanyl overdose.
The late MLB player's official cause of death is listed as fentanyl intoxication and his death has been ruled an accident ... according to the Los Angeles County Medical Examiner.
As we reported ... 43-year-old Sean died back in May, when he was found unresponsive next to his car in a Long Beach parking lot outside his son's Little League baseball game. He was pronounced dead at the scene.
Sean was a coach on his son's team, and folks got worried when he didn't show up for the start of the game. That's when they went looking for him, and found his body.
As a player, Sean won back-to-back Little League World Series titles in 1992 and 1993 with the Long Beach all-star team. He became the first American-born pitcher to throw back-to-back no-hitters, earning him an appearance on the "Late Show With David Letterman."
Sean was signed to play college baseball at USC, but decided to go pro instead. He eventually made it to the Majors, playing 7 seasons with the San Diego Padres, Tampa Bay Devil Rays, Arizona Diamondbacks and Minnesota Twins.
He also won an Olympic gold medal with Team USA at the 2000 Summer Olympics in Sydney.
Sean told ESPN in 2011 that he struggled with drug and alcohol abuse during his final seasons in MLB.