"We are trying to bring in a fullback who plays abroad but is eligible for the Champions League," Milan chief executive Adriano Galliani told reporters before being spotted at Espanyol's offices.
The 21-year-old would be Milan's fourth recruit in January after Antonio Cassano, Urby Emanuelson and Mark van Bommel.
Fifth-placed Inter Milan, who are close to signing Sampdoria striker Giampaolo Pazzini according to media reports, have suspension and injury worries for Sunday's visit of Palermo.
Dejan Stankovic and Ivan Cordoba could both be out for a month with thigh and shoulder injuries while Cristian Chivu is banned. Wesley Sneijder is still not fit so Leonardo will have to field a makeshift side.
Juventus (sixth) host Udinese on Sunday with yet more injuries after Amauri, Simone Pepe and Marco Motta picked up knocks in Thursday's 2-0 Italian Cup defeat by AS Roma.
Second-placed Napoli are signing Espanyol centre back Victor Ruiz, who was pictured in Naples airport, but Sunday's home game with Sampdoria comes too soon for the Spaniard.
Struggling Fiorentina are deciding whether to end Adrian Mutu's banishment after the Romanian striker apologised for quitting training.
"His apology has been appreciated," club director Andrea Della Valle told reporters ahead of Saturday's trip to fourth-placed Lazio.
Cagliari, who host bottom side Bari on Sunday, are on the verge of bringing goalkeeper Federico Marchetti back into the fold, according to media reports in Sardinia.
Italy's World Cup keeper has not played all season after falling out with the club's president but a move to Genoa fell through and he may now stay.
