Conor Gallagher is expected to return to training at Chelsea's Cobham training ground on Wednesday after landing back in London with his Atletico Madrid transfer in the balance.
The England international, 24, was pictured in the La Liga club's Metropolitano Stadium on Saturday and spent five days in a hotel in Madrid but has been unable to complete his £33m transfer.
His move was halted because Chelsea's £34.5m deal to sign Spanish striker Samu Omorodion collapsed over personal terms on Sunday.
The Spanish club need to make one major sale to fund their move for Gallagher after signing Manchester City striker Julian Alvarez for £81.