Bolton defender David Wheater is set to be out for up to nine months after injuring his cruciate ligament against West Brom on Sunday.
The 25-year-old centre-back fell awkwardly during the 2-2 draw against the Baggies at the Reebok Stadium.
A statement on Bolton's official website read: "Scans have revealed that David Wheater has ruptured his anterior cruciate ligament in his right knee.
"The defender picked up the injury when he landed awkwardly during yesterday's home game against West Bromwich Albion.
"He is expected to be out of action for up to nine months."
By the time he returns to action, the Trotters could be a Championship side as they face a battle for Premier League survival on the final day at Stoke.
Wheater's injury is the latest mishap in a calamitous season for Owen Coyle's men.
Lee Chung-yong and Stuart Holden have both been missing for much of the season through serious injury, while Fabrice Muamba is recovering from an on-pitch cardiac arrest against Tottenham in March.