Former Univ. of Alabama running back Ahmaad Galloway -- who played for Tide from 1999 to 2002 -- died from an accidental overdose ... officials tell TMZ Sports.
The Office of the Medical Examiner in St. Louis said Friday the ex-football player died from a lethal combination of fentanyl, ethanol and xylazine.
He was just 42 years old.
As we reported, Galloway was found dead in his home on Jan. 9 ... after he failed to show up for his gig as an eighth grade teacher at Compton-Drew Middle School in St.