Striker Jon Dahl Tomasson is likely to be ruled out of action for Feyenoord until the new year.
The 34-year-old, who is in the final year of his contract at De Kuip, suffered a thigh injury whilst playing for Denmark at the World Cup.
Feyenoord coach Mario Been fears the former Newcastle attacker could now be unavailable until January.
He told the Algemeen Dagblad website: "I have long hoped to have him back quickly, but the messages I get now are far from optimistic.
"It is still at least a few weeks. I fear he is unavailable for the winter."
Tomasson sustained a thigh injury when coach Morten Olsen had already made his three substitutions during the World Cup group stage match against Japan.
"This seriously aggravated the injury," said club doctor Casper van Eijck.
Tomasson was initially expected to resume training at the beginning of September. But Van Eijck realised there was more to the problem when Tomasson was forced out of a light fitness session last month.
"There is an added injury - a muscular injury," he said.
"It is a complex issue and annoying for the club and especially for Jon himself."