According to a report by British media outlet Sun, Scottish Premiership side Celtic are allegedly leading the race for highly-rated Blues centre-half Tomas Kalas.
The Czech star, capped 18-times, presently on loan at English Championship side Bristol City, has been a vital figure in the Robins backline this season as they pursue a Premier League play-off spot.
And manager Neil Lennon is thought to be considering a permanent stay for him as the player builds for European football next term.
With star player Dedryck Boyata believed to leave and Felip Benkovic and Jeremy Toljan due to go back to their parent clubs, Celtic are already planning for major strengthening in the backline.
Head coach Neil Lennon met with Celtic chief executive Lee Congerton this week to talk about possible acquisitions to strengthen their options in defense.
Scottish premiership giants Rangers are also being linked with the him, who can also play at right-back or centre back, with manager Steven Gerrard alleged to be keen on the 25-year-old star.
Tomas Kalas was born in the town of Olomouc and began his professional football career with local side Sigma Olomouc.
After greatly impressing scouts, he joined Premier League giants Chelsea for £5.2 million 2010.
He defender is presently the West London club’s longest-serving member of the squad, but he has started just two English Premier League matches ever since.
Chelsea boss Maurizio Sarri might also be looking to keep Kalas at Stamford bridge as current club centre-half’s Garry Cahill and David Luiz ageing and Rudiger, Christensen not performing to the required level so far this season.
Fans have shown their displeasure with the performances of Brazil international defender David Luiz and England star Cahill, and a departure in the summer cannot be bet against, which could create space for Kalas to return to Stamford bridge in the summer.