NFL's Brandon Browner Investigated for Alleged Assault ... On Baby Mama's Dad

Seattle Seahawks cornerback Brandon Browner has been named in a police report -- by a man who claims the NFL star attacked him at an L.A. County home ... TMZ Sports has learned.

The Pomona Police Dept. confirms ... cops were called to a residence around 8 PM on Tuesday to respond to an incident in which Browner allegedly attacked the father of his baby mama.

Law enforcement sources tell us ... the alleged victim claims he had been arguing with Browner when the NFL star became violent and attacked him in the driveway.

We're told Browner -- a 2-time Super Bowl champ -- left the scene in his white Bentley before cops arrived.

The Pomona PD confirms the alleged victim filed a police report and complained about an injury to his hand.