Michael Olise has reportedly reaggravated the hamstring injury that has kept him out of action so far this season.
The young French wide man tore his hamstring while on duty at the Euro Under-21s over the summer, and has been absent since.
Having missed Crystal Palace's first five games, it was believed that he was edging close to a return for the Eagles.
However, the Evening Standard claims that Olise has suffered a severe setback and will now be absent for a significant length of time.
The report states that Roy Hodgson is set to be without the 21-year-old until after the October international break at the earliest.
In his absence, Palace have made a reasonable start, taking seven points from their opening five, with victories coming against Sheffield United and Wolverhampton Wanderers.
However, losing last season's Player of the Year is a huge blow, considering that Olise recorded 11 assists in the Premier League last season.
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Those numbers saw England's elite begin to circle, and even Hodgson admitted over the summer that it would be very difficult for the club to hang on to the player.
Once Chelsea activated Olise's £35m release clause, it looked as though he would be on his way, but in a shock U-turn, Palace managed to tie him down to a new contract instead.
With the release clause removed, Olise could attract an even bigger transfer fee next summer, should he get back fit and firing on the pitch.
For the time being though, the winger is set to miss Palace's upcoming games against Fulham, a league and cup double against Manchester United, and Nottingham Forest.
One positive for the Palace faithful though is that manager Hodgson will return to the sidelines for their trip to Craven Cottage at the weekend.
The 76-year-old was taken ill on the morning of their 3-1 defeat at Aston Villa over the weekend, but he has since returned to take training and will be present in the dugout on Saturday.
Paddy McCarthy took temporary charge for their trip to Villa Park, where Palace conceded three goals in the dying minutes to squander a lead given to them by Odsonne Edouard's early second-half strike.
