The summer transfer window has so far seen multiple senior players depart Stamford Bridge in a wide-reaching clearout before Mauricio Pochettino takes charge of the squad for the first time next week.
Among the next to leave is set to be Spanish defender Azpilicueta after the Blues agreed a deal with Atleti.
Chelsea are happy to sanction the move for either a nominal fee or as a free transfer despite the 33-year-old signing a two-year contract last summer.
Azpilicueta’s agreement to stay 12 months ago came at a time when the west Londoners were struggling for numbers in central defence, and also saw him turn down a move to his homeland with Barcelona.
It was also previously recognised between the player, then-director Marina Granovskaia and then-owner Roman Abramovich that he would be allowed to leave at a moment of his choosing should he receive a satisfactory offer, as thanks for his years of service to the club.
Chelsea paid Marseille just £7million for Azpilicueta in the summer of 2012 and he has gone on to make over 500 appearances for the team in mutliple positions across the backline.
LIVE BLOG: Follow all the latest transfer news and rumours
Along with two Premier League titles, an FA Cup, League Cup, Club World Cup and two Europa Leagues, he captained the team to their Champions League final triumph two years ago.
So far this summer, Chelsea have banked in the region of £140m from player sales following the £17m exit of Ruben Loftus-Cheek on Friday. As previously reported by Standard Sport, Charlie Webster has now completed his loan move to Dutch club Heerenveen.
