Newcastle have confirmed Haris Vuckic will miss the rest of the season after suffering cruciate ligament damage.
The 20-year-old Slovenian international sustained the injury the Newcastle U21s 2-1 victory at Aston Villa on Monday evening.
A club spokesman said: "Haris Vuckic will be sidelined for the remainder of the season after rupturing his cruciate ligament in his left knee.
"Having been assessed by the club's medical staff, it has been confirmed that Vuckic will not play again during the 2012-13 campaign."
Vuckic signed a three-and-a-half year deal at St James' Park in January 2009 but has failed to established himself in the first team as yet.