Chelsea are interested in Barcelona's Sergi Roberto but have yet to make an offer, sources close to the Premier League club have told ESPN FC.
Antonio Conte is looking to bolster his squad ahead of their Premier League title defence and Roberto, 25, is among his list of targets.
The Spain international, who can play in midfield as well as defence, has a £37.5 million buyout clause in his contract.
Conte has made a new full-back one of his top priorities as he wants to bring in competition and cover for Victor Moses on the right flank.
Moses excelled in Conte's 3-4-3 formation last season, but Chelsea want cover in every position next season as they prepare to battle for honours on four fronts next season after returning to the Champions League.
Chelsea tried to sign Danilo from Real Madrid for the right flank role but lost out to Manchester City and are now considering a move for Roberto.
Roberto played most of last season at right-back last season, making 40 appearances in all competitions for Barca, but his place is under threat following the arrival of Nelson Semedo from Benfica.
Chelsea have so far signed Willy Caballero, Antonio Rudiger, Tiemoue Bakayoko and Alvaro Morata this summer, and more new faces are expected to arrive at Stamford Bridge before the transfer window shuts next month.