Fulham duo Tom Cairney and Terence Kongolo have been ruled out of the start of the new campaign.
Neither have recovered from injuries suffered last season.
A persistent knee problem has plagued Whites captain Cairney since last summer.
Defender Kongolo also suffered a knee injury, in a tackle involving Wolves’ Adama Traore in early April.
The Netherlands international joined Fulham on a permanent deal a year ago but has played just one full game since.
“We hope he (Kongolo) will be ready soon,” said boss Marco Silva.
“But it’s not an easy thing, and over the next few weeks we have to see how he can be.
“Tom at this moment is not fully fit yet. We are working with him to get him as soon as we can fully fit and in condition to show his quality.”
Silva believes a fully fit Cairney bossing Championship midfields, as he did in 2019-20, would make a huge difference.
The Portuguese said: “He is a key player for us, very important in the last promotion, and of course he is really important for me – a key player for me for sure.
“Now it is up to us to get him back in condition as soon as possible in a really important zone of the pitch.”