Peterborough United striker Joe Gormley could be sidelined for up to a year after snapping the cruciate ligaments in his left knee.
Former Irish League top scorer Gormley suffered the injury during a reserve team game against Norwich City last week and will have surgery next week.
Gormley, 25, starred in pre-season but struggled for form when Posh's League One season started.
The forward won back-to-back Irish Premiership titles with Cliftonville.
Gormley, 25, moved to London Road in June after scoring 40 goals in Northern Ireland for Cliftonville in 2014-15.
He was named the Northern Ireland Football Writers' Player of the Year in 2014.