Oscar Taveras -- Cops Don't Believe He Was Drunk ... During Fatal Crash

Officials in the Dominican Republic do NOT believe alcohol was a factor in the crash that killed St. Louis Cardinals outfielder Oscar Taveras and his girlfriend ... TMZ Sports has learned.

We spoke with reps at the Metropolitan Police Department in the D.R. who tell us ... Taveras was driving "very, very fast" on a wet road when he lost control and slammed into a huge tree.

Both Taveras and his GF were killed in the crash.

Officials tell us an autopsy is currently being conducted on Oscar -- but we're told there was no immediate evidence at the crash scene to lead officials to believe he was drunk behind the wheel.

Officials tell us the weather may have played a role -- because it had been raining around the time of the accident and the roads were slippery.

We're told ... Taveras is not the first person to have lost control and slammed into that particular tree -- another person died in the same exact spot last year under similar weather conditions.