Detectives had been hoping to speak to the man at the weekend after he was found in a ‘distressed’ state at the side of the A66 in Middlesbrough last Thursday.
The 40-year-old remains in hospital.
The man, who has not been named, was found with serious wounds ‘to his groin area’.
The 40-year-old remains in hospital and is said to be in a stable condition.
A Cleveland Police spokeswoman told BuzzFeed officers had visited the man on numerous occasions but had been unable to get a detailed statement.
A spokesperson is quoted by the BBC as saying: “We are looking at various lines of inquiry.
"However we have still to obtain an account from the man who remains in hospital and in a stable condition.
"We would ask anyone with information to contact us as this may help progress our inquiries."
A 22-year-old arrested over the attack has been released on bail.