Ex-MLB Star Brad Halsey -- NO BOOZE or DRUGS at Time of Mysterious Death

EXCLUSIVE

Former baseball star Brad Halsey was clean and sober when he fell more than 100 feet to his death in a remote area of Texas ... TMZ Sports has learned.

Halsey died on Halloween from blunt force trauma ... according to the docs we obtained. Sheriff's deputies in Halsey's hometown of New Braunsfels, TX say he either jumped or fell off the cliff which was on private property.

The autopsy report says Halsey's body was screened for a slew of drugs, including ... opiates, cocaine, oxycodone, barbiturates, amphetamines, marijuana, benzodiazepines ... and many more -- but pathologists found nothing. Same result for alcohol.

Halsey had pitched for the Yankees, Diamondbacks, and A's. In 2006, he famously gave up Barry Bonds' 714th career home run ... tying Babe Ruth for #2 on the all-time list