Bolton Wanderers will have to wait to field new signing Blerim Dzemaili after he suffered a serious knee injury while training with current club FC Zurich.
The 21-year-old Switzerland midfielder was due to link up with the Trotters in the summer, having tied up a move to England in January, agreeing a two-year contract to start in June.
However, Dzemaili is now set for a trip to the USA to undergo surgery and is unlikely to be seen in action much before Christmas.
Manager Sam Allardyce told the club's official website: ""I'm very disappointed for the lad.
"It's great shame for him, but we will put him through our rehabilitation programme and hope to get him back in action as soon as possible."
Allardyce had said at the time of Dzemaili's agreeing to join Bolton: "Blerim is a fantastic player, who has played for the best team in Switzerland for the past three years.
"For someone so young, he has a wealth of experience. I am excited by the prospect of working with him next season."