Former Dolphins great Mark Duper has been arrested and accused of striking a child, knocking him unconscious. 

Investigators say he punched, body slammed, and choked his 17-year-old son -- over the boy not picking up his hat from the floor. Duper told police his actions were in self defense. It's the third time in the last ten years Duper has been jailed for acts of violence. 

2013 has not been a kind year for Dolphin legends...