Former Alabama running back Ahmaad Galloway -- who rushed for 17 touchdowns in his Crimson Tide career -- has died ... TMZ Sports has confirmed.
He was just 42 years old.
According to principal Susan Reid at Compton-Drew Middle School in St. Louis, where Galloway was teaching eighth grade English, Galloway was found dead on Monday.
Reid tells us the former tailback, who was drafted by the Denver Broncos in 2003, failed to show up to work ... prompting concerned school leaders to ask for a welfare check at his home.
Reid said when officials entered Galloway's apartment, they discovered he was deceased. A cause of death is not yet known.
Reid said Galloway was a beloved instructor at the school ... and had just attended a students' basketball game on Saturday, showing no signs of trouble.
"He was an excellent teacher," Reid said. "He bonded with his students, particularly those who were interested in athletics."
Galloway played for the Tide from 1999 to 2002, running for 1,830 yards. Following his selection in the '03 NFL Draft, he bounced around the league ... but never logged an official stat in a game.