Fulham boss Slavisa Jokanovic has revealed that his side's activity in the transfer window is "not finished".
However, Jokanovic told reporters at a press conference that he wants to sign more defenders before Thursday's deadline, with Mawson, who is currently recovering from surgery, and Maxime Le Marchand the only arrivals in that department so far.
"Our business is definitely not done," the manager said. "I'm not the first who complains about transfer business. I'm not complaining. We need some additions. We need backups in some positions.
"Only Tim Ream is in the squad. [Maxime] Le Marchand has come from Nice, he's definitely part of the team but we need to try to strengthen in the next few days ahead of us. I mentioned many players in the defensive line, I bring [in] only one. You have the opportunity to check the game, you'll have some kind of opinion about the squad. This is the situation. We have time ahead of us, but we must be fast."
Fulham face Crystal Palace in their opening Premier League fixture next weekend.