Inter Milan chief Giuseppe Marotta has given clubs hope of signing either Milan Skriniar or Alessandro Bastoni.
Spurs have made Bastoni their number one centre-back target, while Skriniar is also an option.
Blues boss Thomas Tuchel is desperate to sign a centre-back following the departures of Antonio Rudiger and Andreas Christensen.
He told Radio Rai: "It's certainly easier to replace a centre-back than a striker ... we will probably be forced to sell someone in that position."
However, asked if the club would part with striker Lautaro Martinez, he replied: "Lautaro is a key player for our plans."