Aston Villa defender Jores Okore is out for up to nine months after rupturing the anterior cruciate ligament in his right knee.
The 21-year-old Denmark international was signed in the summer for a fee in the region of £4million and now faces a long road back.
Okore limped from the pitch after half an hour of Villa's 2-1 defeat by Newcastle on Saturday and was sent for an MRI scan.
Manager Paul Lambert feared the worst for his new centre-back and that news was confirmed on Monday evening.
A club statement read: "Following clinical examination and the results of an MRI scan, the club can confirm that Jores Okore sustained a ruptured anterior cruciate ligament injury in his right knee in the game against Newcastle on Saturday.
"Jores will undergo surgery in due course and he could be sidelined for a period of up to nine months."
Okore's injury occurred during an apparently innocuous collision with Newcastle striker Loic Remy.
It boosts Republic of Ireland international Ciaran Clark’s hopes of establishing a role in the Villa first team with Lambert’s hand also restricted by the closure of the transfer window.