Police were called by the London Ambulance Service at 4am on Sunday, 22 August to a man found with a leg injury outside of a pub on Ripple Road in Barking.
The 46-year-old victim remains in hospital where he continues to receive treatment.
Officers believe that the man was driven into by a car which then left the scene.
A 39-year-old man was arrested in connection with the incident on Monday, 23 August. He was released under investigation pending further enquiries.
Detective Constable Chris Hunt, from East Area CID, said: “This incident has left a man with a significant injury and one which will take a long time for him to recover from.
“A number of people have come forward with information but we believe there were others in the area at the time of the collision who may be able to provide some key details.
“If you were in Ripple Road between 3.45am and 4am on Sunday please think about whether you saw anything and come forward to police.”
Anyone with information is asked to call police via 101 quoting reference Cad 1411/22Aug.