#3 Ronald Araujo
Ronald Araujo has been one of the better players at Barcelona this season. Although Xavi has brought the Nou Camp outfit back on track, the centre-back has been incredibly consistent throughout the campaign.
At only 23, Araujo is already a starter for the five-time Champions League winners. The Uruguyan international is aggressive in tackles but rarely runs the risk of getting red carded.
His passing range is also commendable and is now playing the tiki-taka, which Xavi has employed so eloquently at Barcelona. Chelsea need somebody who is defensively sound and just as creative with his passing. Araujo certainly meets the job requirements.
The South American ace is also in the final 18 months of his contract and if the La Liga club needs the money, he is a sellable asset. If they do decide to let him go, the Blues could consider the Barcelona star as a viable option to replace Christensen.
#2 Matthijs de Ligt
Matthijs de Ligt is arguably the best centre-back in the world aged 22 or under. The Dutchman has continued to give sensational displays for Juventus this season as well and has been key to their ambitions of sealing a top-four spot in Serie A.
The centre-back is an able passer of the ball and has great awareness. One of the advantages of having De Ligt is his versatility as he knows how to play in a back four and a back three. On top of all of this, the Dutch international is also a threat in set-pieces and often gets his head to the ball first during corners.
With Tuchel also appreciating versatile centre-backs and players who can be dangerous in set-pieces, De Ligt could be an ideal replacement for Christensen.
#1 Jules Kounde
Jules Kounde has been linked with a move to Chelsea for nearly a year now. The Sevilla ace has been wonderful in Spain for the last couple of years and has been linked with a move to England since last summer.
The French international is a complete package and only a few defenders in world football are currently better than him. The centre-back is technically sound and adept in nearly every aspect of the game.
His partnership with Diego Carlos has seen Sevilla maintain the most frugal defense in La Liga this term. His agility, strength on the ball and creative passing make him one of the hottest properties in European football.
Chelsea have been strongly linked with him and if Christensen does leave in the summer, Kounde could be considered a priority summer signing for the Blues.