Inter Milan will reportedly have to sell 32-year-old Ivan Perisic before they grant Chelsea permission to sign wing-back Achraf Hakimi.
The Blues are competing with Paris Saint-Germain for Hakimi's signature, but Chelsea are believed to have lined up a swap deal involving Marcos Alonso to beat the French giants to the Morocco international.
Hakimi is a versatile player who can play right midfielder and either side as a full-back, however for Chelsea to finalise a deal with Inter for Hakimi, the Italian outfit must offload current wing-back option Perisic.
According to football.london, in order for Inter to accept the player-swap deal involving Alonso, the Serie A champions will need to make room in their squad.
Perisic's contract in Milan is due to expire next summer and he has attracted interest from Bundesliga sides Eintracht Frankfurt and Hertha Berlin, and also Premier League outfits including Arsenal, Tottenham Hotspur and Manchester United.
The Croatian international joined Inter in 2015 and has gone on to score 45 goals and provide 40 assists in 205 appearances for the club, while also going out on loan to Bayern Munich for one season.