Manchester:Valeri Bojinov will be sidelined for at least five months after he seriously injured his knee in Manchester City's 1-0 victory over Manchester United.
City said on Monday in a statement that the Bulgaria striker damaged the lateral and anterior cruciate ligaments in his left knee when he fell early in the game at the City of Manchester Stadium.
Bought from Fiorentina, Bojinov is one of eight signings by City manager Sven-Goran Eriksson.
The victory over United put City at the top of the Premier League after three shutout victories.
The injury has also ruled him out of several games for Bulgaria's national team and he was immediately taken out of the lineup for Wednesday's friendly against Wales.
Bulgaria coach Dimitar Penev was planning on using Bojinov to replace Dimitar Berbatov, who has a groin injury.
Penev called up CSKA Sofia striker Georgi Chilikov into the squad as Bojinov's replacement on Monday.
Berbatov hopes to return for the 2008 European Championship qualifier against the Netherlands on Sept 8.
Bulgaria is second in Group G with 15 points from seven matches, two points behind Romania.