Forest boss Colin Calderwood told the club website: "Nathan has ruptured his medial ligament in his left knee again, so he's out for the season.
"Although it's the same knee, it's a completely new injury."
End of season for Forest striker
Forest boss Colin Calderwood told the club website: "Nathan has ruptured his medial ligament in his left knee again, so he's out for the season.
"Although it's the same knee, it's a completely new injury."