Fulham tried to sign Sporting Lisbon centre-back Marcos Rojo during the January transfer window but as the Portuguese side rejected their £5m offer the English side finally opted to sign former Everton defender John Heitinga instead.
The Cottagers, who are trying to avoid relegation to the Championship, had a very busy transfer window, bolstering the squad with Olymipakos striker Konstantinos Mitroglou, Tottenham Midfielder Lewis Holtby, Everton defender Heitinga and Manchester United youngsters Ryan Tunnicliffe and Larnell Cole.
However Portuguese newspaper A Bola claimed that the London club were frustrated in their attempts to sign Rojo, who was manager Rene Meulensteen's top target to strengthen his defence.
According to A Bola, Fulham launched a £5m bid on deadline day to secure the services of the Argentinian defender but Sporting President Bruno Carvalho immediately rejected the move as they considered the bid very low.
According to the reports, the Portuguese side are willing to let Rojo leave the team this summer, but they wanted to keep the player in January as his value is likely to increase after the 2014 World Cup.
The 23-year-old Argentina international is one of the most promising players in Portugal and is set to make the trip to Brazil next summer after being part of the national team in recent friendlies.
When Rojo's deal failed, Fulham finally decided to complete the signing of Everton centre-back John Heitinga on a free transfer to replace Philippe Senderos, who joined Spanish side Valencia on deadline day.
Apart from the departure of Senderos, Brian Ruiz left Craven Cottage to join PSV Eindhoven, Aaron Hughes joined Queens Park Rangers and Dimitar Berbatov completed a loan move to Monaco.
Fulham are currently on the bottom of the Premier League after their latest 3-0 defeat against Southampton at Craven Cottage.