A man has been arrested on suspicion of causing grievous bodily harm after a man suffered a fractured skull in May.
A 35-year-old man has been bailed to August 15 following an attack on a 33-year-old man found in Pembroke Place, Bampton.
The victim told police he had been assaulted by a man in the village's Market Square between 4am and 8am on May 28.
Thames Valley Police said the victim was helped by a member of the public until paramedics took him to Oxford’s John Radcliffe Hospital.
He had surgery and has been transferred to Witney Community Hospital where he is awaiting further surgery.
Anyone with information should call Dc Joe Stevenson on 101 or Crimestoppers anonymously on 0800 555111.