Atletico Madrid president Enrique Cerezo has confirmed that the club are in talks to bring the 29-year-old back to Vicente Calderon, just a year after moving to the Premier League in a £15.8 million deal.
Mourinho insisted on Sunday that any agreement to sign Filipe Luis is dependent on Chelsea receiving the majority of their initial outlay back, before adding that Mohamed Salah could also be on the move.
"In this moment we need a left-back because I think we are selling Filipe Luis now or tomorrow [Wednesday], but I think we will sell Filipe Luis," Mourinho told reporters.
"We need to go the market, we need to find a club that accepts a bid until 31 August, and we are going for a left-back. In other positions we have no space."
Augsburg left-back Baba Rahman is reportedly being lined up as the Brazilian's replacement.