New Bolton signing Tyrone Mears has broken his leg in training, less than a week after joining the club.
The defender, who completed his signing from Burnley alongside Clarets team-mate Chris Eagles on Friday, will now miss several months of the new season.
Manager Owen Coyle told the club's official website: "Ty went in for a challenge and unfortunately suffered the injury.
"It was desperately unlucky for him and we will make sure that he is fully supported in his rehabilitation.
"He will go for a check and an assessment in a month and that will indicate more accurately the timescale for his recovery."