Diarra's Fulham career could be over after Martin Jol admitted the injury-ravaged 31-year-old will not play again this season.
Jol said: "It is still painful. I think it will be quite complicated without an operation to get him going and fit again. We need to sit down and talk to the surgeon and make a decision, but I think he will out for the next couple of months.
"He was the main man last year when he came in. He gave us a boost again and was one of the most important players. It was quite a boost for us to get a player of his quality, but you have to be fit. If he isn't fit he can do nothing for us."