Chelsea manager Maurizio Sarri is looking to sign Alessio Romagnoli and Mattia Caldara from AC Milan, according to a report.
The 59-year-old is said to have prioritised signing a central defender in the New Year and is closely monitoring the Milan pair.
Italian outlet Calciomercato suggests that Chelsea will attempt to bring in cover at the earliest possible opportunity, with Romagnoli and Caldara topping Sarri's winter wishlist.
Romagnoli only recently renewed his San Siro contract, though, while Caldara joined from Juventus during the summer window, meaning that the Blues may have their work cut out.
Both players are highly rated by the Rossoneri and it is claimed that only a big offer will persuade them to cash in.
Chelsea have won their opening four Premier League games under Sarri, conceding three goals in the process.