• Özil, now set to be out till 2015 , played on at Chelsea • Aaron Ramsey and Mikel Arteta set to return against Hull

Arsène Wenger has sought to clarify the situation surrounding the decision to allow Mesut Özil to play on in the recent game at Chelsea while carrying a knee injury.

Özil, Arsenal’s record signing, faces a spell on the sidelines after scans on international duty with Germany discovered a “partial rupture of the outer band of the left knee joint”. He is now set to be sidelined for up to two months.

It has been suggested Wenger went against the advice of both the player and Arsenal’s own medical staff by keeping Özil on during the Premier League game at Stamford Bridge on 5 October as his side looked to get back into a match they would go on to lose 2-0. However, the Arsenal manager insists there was nothing untoward and he had even stressed to Özil the need to come off if he felt any problems.

Speaking at a press conference for Saturday’s game against Hull, Wenger said: “He did not tell me anything during the game, I did not even know. What happened was that at half-time, just before we went out, the physio told me: ‘Özil has a little pain with his knee, but it is not bad.’

“He wanted to go on and I told him: ‘If you don’t feel well, tell me and I will take you off straight away.’ He never did that during the whole game, and after that I left him on because we were in a position where we needed to score a goal and he can deliver the final ball.

“Then after the game, he went to Germany. With Germany, they thought at the start it was nothing.

“We played on Sunday, on Monday he was off, and on Tuesday they gave him the day off. He was supposed to practise on Wednesday. On Wednesday morning, he said he could still not practise.

“They sent him for a scan, and in this scan they discovered that he had a knee ligament injury which is quite serious.”

Özil is not expected to return to action until the start of 2015.

Wenger added: “That is the only positive, that he will get the rest that he did not maybe have enough of after the World Cup. Although I must say, I gave them until 11 August , Germany played the final on 13 July . That was a month and should be enough after a big competition. He is out for a while now, I think at least six weeks.”

Arsenal have seen several players hit by injury, with Laurent Koscielny out because of an inflamed achilles the latest casualty.

However, Theo Walcott is set to play for the club’s under-21s on Friday after nine months out with a knee injury, and captain Mikel Arteta could feature against Hull, while Aaron Ramsey is expected back for the Champions League tie away to Anderlecht in Brussels. Olivier Giroud should return “ahead of schedule as well”, Wenger said, though the suspension of Calum Chambers for his fifth booking of the season means the manager believes his side will be a bit short defensively against Hull.

Chambers is one player who could be in contention for the England Under-21s at next summer’s European Championship after Gareth Southgate’s squad booked their place with a play-off victory over Croatia earlier this week. Wenger, though, believes that for those who have already been promoted to the senior setup it should be club before country.

“Once a guy has moved up to the full national team, [if] you put him down [to the under-21s] he is never good,” said Wenger. Apart from on the selfish front for us when a guy has played 50 games, it is better that a guy has a good rest during the summer. But most of the time, when they move down, they are not completely at their quality.”