Former Fulham defender Rufus Brevett fears they'll lose Clint Dempsey in the summer.
The USA striker has been linked with Arsenal, Manchester United and Everton in recent weeks.
"Dempsey has been outstanding," Brevett told the Fulham Chronicle. "He's one of those players where you know what you're going to get with him. [Moussa] Dembele and [Andy] Johnson are the same.
"The attacking players they've got [at Fulham] to create things in the final third are very good and I think they need to keep hold of them.
"If you're a player you want to play as high as you can. If one of the top four clubs comes in for him it's going to be very difficult for Fulham to persuade him to stay.
"I'd like to think he'd want to stay at Fulham but it'd be very difficult if a top four team comes knocking on the door."