Former Saints loanee Michail has undergone surgery on a “lower limb fracture”, the Hammers have confirmed
The 34 year old is conscious after being taken to hospital in London following the incident in Epping, Essex on Saturday afternoon.
The update was issued after unverified images of a heavily damaged Ferrari began to circulate online.
A club statement read: “West Ham United can confirm that Michail Antonio is in a stable condition following a road traffic accident this afternoon in the Essex area.
Michail is conscious and communicating and is currently under close supervision at a central London hospital.
“At this difficult time, we kindly ask everyone to respect the privacy of Michail and his family.
“The club will make no further comment this evening, but will issue a further update in due course.”
Antonio, a Jamaican international, was a member of Southampton’s EFL Trophy-winning side in 2009-10 as a loanee from Reading.
He made 39 appearances for the club in all competitions, scoring seven times, including a goal in the final against Carlisle United.
Essex Fire Service also confirmed firefighters had attended the scene and released a man trapped in his car.
A statement read: “Crews were called to High Road, Epping, at 1.02pm this afternoon after reports of a road traffic collision involving one car.
“In arrival, firefighters reported that a man was trapped in his car and worked to release him by 1.45pm. The casualty was left in the care of the Ambulance Service.”