manager Arsene Wenger admits winger Theo Walcott
's knee injury - sustained in training on Friday - is "very bad news" for the Gunners.Walcott has already been ruled out of Saturday's Premier League clash at Newcastle and next week's England
Under-21 internationals.Although the 20-year-old is established in Fabio Capello's senior squad, he has only just recovered from a shoulder injury picked up with the full team in November.It was hoped Walcott could be eased back into action with the Under-21s against Norway and France, but Wenger revealed the forward would now need rest."The bad news we have for us and for England is that Walcott got injured today in training," said Wenger."He will have a scan on his knee today and we are a bit surprised and worried because he was in very good form coming back."That is very bad news for us."Out for the rest of the season would be too long, but certainly he is out of the squad for the Newcastle game tomorrow and he could be out of the squad for England."He will be scanned this afternoon and we will assess his situation tonight."Wenger added: "Theo locked his knee when he was walking back from training, so it could be a cartilage."Training was fully normal and maybe he has done it in training and it came out when he stopped."But we have to see how he responds today. I hope that it is not serious, but he has to be scanned."Wenger hopes the international break does not hamper Arsenal's end-of-season run-in, with almost all of his first-team squad set to be away with their countries - including Croatian hitman Eduardo, who has only just returned from a year out with a broken leg.He said: "Now many of the team go away on international duty and I hope we do not lose players through injuries because many of our players are coming back now from injuries. It looks like we are in a good situation."Cesc [Fabregas] should be fit in two weeks. He is back in full training now and during the international break he has two weeks to sharpen up."Normally, he should be available again against Manchester City
."Arsenal head into a crucial stage of the season with a much more positive outlook, now back up into fourth place in the Premier League following an unbeaten run of 15 matches and also through to the FA Cup semi-final against Chelsea
at Wembley following what was a controversial win over Hull in midweek.The Gunners will face Spanish side Villarreal in the last eight of the Champions League, the team they beat en route to the final in 2006.Wenger, though, is taking nothing for granted this time around, as Arsenal look to secure what could be a semi-final against holders Manchester United
, who must play Porto."It is maybe a good opportunity to play the first game away from home, but at that level it is very difficult to be creative in your statement," he said."It will depend on the quality of your performance and the players available as well."We have learned that to knock any Spanish team out is very difficult."There are many big clubs in Europe who are not in the quarter-finals. We are one of the five clubs who have for 10 consecutive years qualified for the Champions League, so to go to the end of it is our immense desire."