Chelsea must face the prospect of losing David Luiz to Barcelona this summer whether they end the season as Champions League and FA Cup winners or not.
The Brazil international, a €25 million (Dh120m) acquisition from Benfica just 14 months ago, is aware of the Catalan club's approach and is interested in a transfer.
While not unhappy at Stamford Bridge, the versatile defender regards Barcelona - a club with a historic appeal to Brazilian footballers - as a natural progression from Premier League football. Should the deposed Spanish champions lodge their expected bid, the 25 year old is likely to encourage Chelsea to accept it.
Barcelona have prioritised the recruitment of a new central defender as part of a plan to refreshen their squad following the loss of their Primera Liga title to Real Madrid and Pep Guardiola's decision to step down as manager.
Carles Puyol, their captain, recently turned 34 and has struggled with injuries over the past two seasons. Javier Mascherano, regarded as one of football's best holding midfielders before leaving Liverpool for Camp Nou, has been converted to a centre-back but lacks the height and pace to nullify certain opponents.
There are also issues with Gerard Pique whose poor attitude has upset the Barcelona dressing room this season and led to his exclusion from recent key fixtures.
While another Brazil international, Thiago Silva, is Barca's first choice to strengthen the position, AC Milan do not want to let the player leave.
Successive attempts to negotiate a transfer fee have failed to come anywhere close to a resolution with Milan asking €40m for the 27 year old, Barca offering €25m, and the Catalan club beginning to pursue other options.
Javi Martinez, who usually plays in midfield but can operate as a defender, will not be allowed to leave losing Europa League finalists Athletic Bilbao for less than his €40m buyout clause; a sum Barca do not wish to pay as they also plan to recruit at left-back and in attack.
David Luiz, however, is seen as a more accessible target who can also provide options on the left side of defence.
The Brazilian's first full season at Chelsea has been a challenging one pockmarked with high-profile criticism of his adventurous, ball playing style - a characteristic which Barcelona believe they can use to their advantage.
While his performances have improved since Roberto Di Matteo's appointment as interim first team coach and a general tightening of the team's defensive organisation, he still faces significant competition for a starting place from John Terry, Branislav Ivanovic and recent signing Gary Cahill.