Chelsea and England forward Callum Hudson-Odoi was arrested and bailed on Sunday following an argument with a woman.
The Metropolitan Police said officers and London Ambulance Service were called in the early hours of Sunday morning “to a report of an unwell woman”.
The woman was taken to hospital and a man was arrested at the scene and remained in police custody.
Chelsea have declined to comment.
Hudson-Odoi, 19, had made 17 Premier League appearances for Chelsea this season until the COVID-19 pandemic halted the campaign. He made his England debut last year and has a total of three caps for his country.
Hudson-Odoi was the first Premier League player to test positive for coronavirus ut has since made a full recovery.