Arsenal midfielder Emmanuel Frimpong has been ruled out for six to nine months after injuring his knee in training.
The 18-year-old Frimpong damaged cruciate ligaments on Wednesday and could miss all of the season, Arsenal manager Arsene Wenger said Thursday.
''That is a massive blow. A cartilage is three to four weeks but a cruciate like the one Frimpong did yesterday is six to nine months,'' Wenger told the club's online TV channel.
News of Frimpong's injury comes a day after fellow midfielder Samir Nasri underwent knee surgery. The France international is set to be out of action for a ''matter of weeks,'' according to the Premier League club.
Defensive midfielder Frimpong, who was born in Ghana but has played for England youth teams, has come through the ranks at the north London club and was expected to be used by Wenger in the Arsenal first team this season.
He played a prominent role in the Gunners' preseason matches but was not part of the squad in Sunday's 1-1 draw at Liverpool on the opening weekend of the Premier League season.
Frimpong sustained the injury in reserve-team training in Dublin, where the squad is taking part in a friendly tournament.
''I rate him highly and I still have a lot of faith in him but we will miss him,'' Wenger added.
