David Luiz has started just 13 of Chelsea's 30 Premier League fixtures with Jose Mourinho not finding a place for him.
Paris Saint-German is believed to be preparing a €45 million bid, who is seen as an ideal replacement for Alex.
Mourinho has preferred John Terry and Gary Cahill in central defense, while Nemanja Matic is preferred in the defensive midfield role.
Chelsea also sold the highly talented Juan Mata to Manchester United to help fund future moves.