Chelsea youngster Izzy Brown faces a lengthy spell on the sidelines with a knee injury.
Brown, on a season-long loan at Brighton, suffered the injury during their FA Cup win against Crystal Palace on Monday.
A scan has subsequently revealed the 21-year-old has sustained anterior cruciate ligament damage.
Brown must undergo surgery, almost certainly ruling him out until next season.
The England Under-20 international has made one first-team appearance for Chelsea, who signed him from West Bromwich Albion in 2013.
He has previously been on loan at Huddersfield, where he played a key role in their promotion last season, Rotherham and Dutch club Vitesee Arnhem.