Manager Martin Jol lost two of his most important players to Tottenham in the final week of the transfer window with both Mousa Dembele and Clint Dempsey moving across London to White Hart Lane.
But Diarra, 31, believes the club's new signings Hugo Rodallega, Mladen Petric and Dimitar Berbatov can all add something to the squad over the course of the season.
"Dimitar, Hugo and Petric can help the team very well," he told Fulham's official website.
"They are three very good players and they will be very important for the team.
"We saw against West Ham some of what they can do but, with time, they can be better and start scoring goals."
Source: team talk
Source: team talk