Arsenal will consider letting Nuno Tavares leave the club this summer if they can sign a left-sided defender.
Tavares is a loan target for Marseille as they prepare for a return to the Champions League next season after finishing second in Ligue 1.
Atalanta are also interested in a move for the 22-year-old, who was the understudy to first-choice left-back Kieran Tierney last season and had some shaky moments when he came into the team.
Arsenal are targeting a move for highly-rated Ajax defender Lisandro Martinez as they look to continue their summer spending after agreeing a £34million deal to sign midfielder Fabio Vieira from Porto.
Martinez, who is valued at around £30m, would provide competition for centre-back pair Ben White and Gabriel but can also play at left-back.
If Arsenal can secure Martinez, they could be willing to sanction the exit of Tavares.
Real Sociedad are also reported to be interested in a move for Tavares, who joined Arsenal from Benfica for around £8m last summer and made 28 appearances.
Atalanta have identified him as a target but their head of senior recruitment Lee Congerton has admitted a move could be difficult.
Congerton said: “I have followed Tavares since he was playing for Benfica’s youth team, he is a strong player. But Tavares is under contract with Arsenal - and it is really difficult to sign players from Premier League clubs.”
