Sgt. Eric Diauto said police responded to the parking lot of the restaurant at 11:41 p.m. to find the 22-year-old victim had sustained a possible life-threatening head injury from hitting his head on the ground after getting punched.
Police arrested another 22-year-old Bourne man on assault charges and an arraignment is scheduled for Monday.
Diauto said a cause of the altercation had not been determined and witnesses described the assailant as a friend of the victim.
Rescue crews transported the victim to the Pocasset Fire Station where they met a Medflight crew.