Fulham are intent on replacing Aleksandar Mitrovic in the final week of the window, after the striker joined Al Hilal for a club-record sale worth £46million. They are interested in Flamengo’s Pedro and Duvan Zapata at Atalanta.
Raul Jimenez, Adama Traore, Calvin Bassey and Willian have come in this summer, but Fulham also lost five players whose contracts expired as well as three loanees who returned to their parent clubs.
"From last April, the plan was clear", said Silva. "It's no surprise what we need. We have just two full-backs in our squad — one right-back and one left-back. We need two more.
"We have to sign at least five players until the end of the market. We have to."
Fulham visit Arsenal tomorrow, a side they last beat in 2012 and have never beaten away from home in their history.
"That shows how big the task is", Silva added. "Those are the facts and I cannot go against the facts. Arsenal, when they play against 80 or 90 per cent of teams at home, are the favourites.
"It's a big challenge for us, but we like big challenges. We showed that last season and we have to start showing again how much we like these challenges."