Alvin Kamara Sued Over Alleged Vegas Beatdown, Man Seeking $10 Million

New Orleans Saints superstar Alvin Kamara is being sued for allegedly attacking a man outside a Vegas nightclub during Pro Bowl weekend in February ... TMZ Sports has confirmed.

The plaintiff, Darnell Greene, claims he was among a group of people waiting for an elevator near Drai's around 6:30 AM ... when Kamara put his hand on his chest to keep him from entering the lift.

Greene says the running back then shoved him into a wall and repeatedly punched him in the face.

The lawsuit claims Greene tried to escape ... but AK chased him down and attacked him, causing injuries including a broken orbital.

Now, Greene has lawyered up ... and is seeking $10 million in compensatory and punitive damages.

"The brutal violent assault broke Greene's orbital lobe, severely injured his shoulder, back, and neck, and left him temporarily unconscious and helpless on the floor," the lawsuit states.

Greene claims Kamara boasted about his role in the alleged beatdown ... saying, "I connected with the [expletive]’s jaw so hard,'" according to the suit.

The alleged injuries were so bad, Greene states he will need to undergo multiple surgeries to repair the damage done to his body.

"Medical testing confirmed a disfiguring facial fracture to Greene's right orbital bone, blunt force trauma to his head, multiple disc protrusions, and structural tears in his shoulder," the suit says.

The lawsuit provides pictures of Greene's bloody face following the alleged beatdown ... as well as still shots from security footage -- and Greene claims NFL commissioner Roger Goodell hasn't taken any action to discipline Kamara.