Chelsea boss Andre Villas-Boas has confirmed the club have bid for Porto full-back Alvaro Pereira, but says he is "not very confident" of signing him.
The 25-year-old left-sided wing-back played under Villas-Boas at Porto and helped Uruguay to win the Copa America title during the summer.
"The only thing I can confirm is we have made a bid and are very far apart in terms of numbers," Villas-Boas said.
The manager said he was "not very confident" a deal could be finalised.
Villas-Boas has made several expensive additions to his squad since taking the reins at Stamford Bridge in June.
Teenage Anderlecht striker Romelu Lukaku and Valencia midfielder Juan Mata joined the Blues earlier this month for reported fees of £20m and £23.5m respectively.
Tottenham's Luka Modric is another player he is keen to recruit but at White Hart Lane.