The 19-year-old was released on bail on Monday. Police were called to his Battersea apartment in the early hours of Sunday morning by a woman he allegedly met online and invited to his residence.
Neither Hudson-Odoi, his representatives nor Chelsea have publicly commented on the situation, and there was speculation he would be asked to self-isolate after having been in contact with a stranger at his private address, breaching coronavirus social distancing guidelines implemented by the government.
Hudson-Odoi was one of the first UK-based players to test positive for COVID-19 in March, but has now tested negative for the virus.
Chelsea head coach Frank Lampard allowed Hudson-Odoi to train at the club's Cobham base on the first day that Premier League clubs could step up their preparations for a possible return to competitive action by introducing "Phase 1" group training of no more than five people, all maintaining social distancing.
Lampard and the club's medical staff decided Callum-Odoi could participate, but it remains to be seen how the Blues will handle the off-field situation.
The England international was not charged, but police visited his address to investigate further and he is due to speak with officers again next month.
A police spokesman said: "Police and London Ambulance Service were called at 03:53hrs on Sunday, 17 May to a report of an unwell woman.
"When emergency services attended, a woman reported that she was raped. She was taken to hospital.
"A man was arrested at the scene on suspicion of rape. He was released from custody and bailed to return on a date in mid-June."
Tuesday's hourlong session was noncontact, with players told to arrive separately in their training kits and given just 15 minutes at the end for any necessary treatment before the next group arrived.