#3 Marquinhos
27-year-old Paris Saint Germain captain Marquinhos has long been linked with Chelsea. Entering the final years of his PSG contract, which runs until 2024, the Brazilian has matured into one of the world's finest defenders. His comfort on the ball, quickness and ability to play in holding midfield make Marquinhos the perfect tactical fit. Not to mention getting to play under a coach who has previously expressed great admiration for his ability.
Thiago Silva has served as a mentor for Marquinhos, both in club and national colors. He could further serve to entice his signature at Stamford Bridge next season, should he hang up his boots and transition into a coaching career.
#2 Declan Rice
Declan Rice has long been on Chelsea's radar, with former manager Frank Lampard pushing heavily to bring the once Chelsea star home. The England and West Ham defensive midfielder's impeccably tidy and disciplined displays have established him among the top midfielders in the Premier League.
The England international is versatile and could comfortably slot in at center back, especially as the "spare man" in the backline, combined with a freedom to create. Given his history with the club and close personal relationship with Mason Mount, a reunion sounds plausible, unless Rice's Euro 2020 heroics have outpriced his services.
#1 Andreas Christensen
An unconventional option for Chelsea's usual big money transfers, Andreas Christensen has certainly looked the part. Some might say the Danish international has already overtaken Thiago Silva in the pecking order to establish himself as the first-choice center back in the three-at-the-back system.
With the impending arrival of Jules Kounde and the welcome emergence of Trevoh Chalobah, Chelsea's back three seem sufficiently covered, with Andreas Christensen at the heart of defense.
The giant center back has developed a refinement, maturity and calmness to his game that's resulted in the Blues' resolute defense. As a Chelsea youth product, he had to reach the first team the hard way, with experience in Germany and the Netherlands. But Christensen now looks set to be a fundamental part of the team for the first half of this decade at a minimum.