Ex-Oakland Raiders star cornerback Sean Smith is a free man -- he was released from jail Tuesday morning ... roughly 5 months into his 12-month sentence.
Smith has been locked up since March 13 -- when he pled guilty to felony assault in the brutal attack of his sister's boyfriend during a July 4, 2017 incident in Pasadena, CA.
The victim suffered major injuries including 5 facial fractures -- and required major reconstructive surgery including having a metal plate inserted into his face.