Arsenal officials were reportedly spotted in Lisbon after scouting Benfica left-back Alex Grimaldo.
The 23-year-old has been a standout performer for the Eagles this season, scoring six and assisting a further five in 21 appearances.
According to A Bola, Grimaldo has been a long-term target for the Gunners who are unconvinced with their current options.
Sead Kolašinac has been a valuable attacking outlet but struggles defensively, with Nacho Monreal more prone to injury as he approaches his 33rd birthday.
The former Barcelona defender possesses the necessary attributes to be a full-back under Unai Emery while still having room to develop.
According to Mundo Deportivo, Atlético Madrid are also interested in Grimaldo which would drive his price up this summer.