More problems for ex-Oakland Raiders center Barret Robbins -- the troubled 42-year-old was arrested outside of a bar in Boca Raton, Florida after allegedly getting violent with several people.
TMZ Sports has learned ... Robbins was taken into custody around 12:30 AM on Tuesday -- after witnesses say he attacked a person inside of a bar, struck another person outside the bar ... and then roughed up a mother and her daughter after that.
One witness says after the incident, Robbins sat down at the scene and waited for cops to arrive.
He was eventually arrested on 2 counts of felony battery. But instead of locking him up in jail, Barret was transported to a nearby mental health facility.
According to court documents, Barret is unable to pay for his own lawyer -- so he was appointed a public defender.
Barret famously disappeared before the Raiders took on the Bucs in Super Bowl XXXVII in 2003 -- and it was later determined that he was bipolar and had gone into a manic episode.
After his football career ended, Robbins was arrested several times for violent crimes -- including attacking a security guard and brawling with police in Miami Beach.