Ex-Raider Barret Robbins: Terrifying 911 Call States 'He Just Punched a Kid in the Face'

TMZ Sports has obtained the 911 call made by a witness who saw ex-NFL lineman Barret Robbins on a violent rampage in Florida last week ... and it sounds terrifying.

The caller initially reports a "huge drunk man just literally walked into (a pub) punched this kid in the face" in the late hours of August 8th.

We broke the story ... the former Oakland Raiders lineman (who was listed at 6'3", 320 during his playing days) was leaving a bar in Boca Raton when the rampage began.

The caller says Robbins was yelling to himself and waving his hands around -- before attacking two innocent women outside of a nearby hotel.

"He just punched a woman. He just punched a woman outside of Best Western. Are you OK?! We called the police ... We have to do something. A bunch of people are about to jump him. I have to go, please hurry."

Cops raced to the scene and Robbins was eventually arrested for felony battery. He was transported to a jail and then a mental health facility.

Robbins has a well-known history of mental health issues -- which became public after he went MIA in the hours before Super Bowl XXXVII.