The 25 year old victim was attacked at a car park to the rear of a local hotel in Castle Street, Ballymoney in the early hours of Sunday 26th July.
The suspect has been bailed pending further enquiries.
Detective Sergeant Chris Wilkinson said: “The injured man remains in hospital in a critical condition.
“We continue to appeal to anyone who was in the area of the hotel car park at around 1.30 am on Sunday morning and witnessed this incident to contact detectives in Coleraine on 101.
“We would also be keen to view any footage available, that may have been recorded on phones by people in the area, which may help us to establish a timeline of events.
“Again, the number to call is 101.”