Arsène Wenger has said that Alex Oxlade-Chamberlain will miss up to seven weeks of Arsenal’s Premier League title challenge as a result of the “quite serious” knee injury that forced the England player to limp out of Tuesday’s Champions League defeat by Barcelona.

Wenger suggested that the injury did not appear severe enough to rule the midfielder out of this summer’s European Championship but admitted that club and country were waiting anxiously on the results of a scan. A seven-week absence would sideline Oxlade-Chamberlain until mid-April and allow him a month of competitive action to prove his readiness for the Euros.

Oxlade-Chamberlain sustained the injury in a tackle by Javier Mascherano but Wenger does not attribute any blame to the Argentinian and is also satisfied that the injury is not a recurrence of the knee trouble that kept Oxlade-Chamberlain out of action for several months in 2014.

“It is a new injury,” said Wenger. “When he has been cut in two by Mascherano he did his knee. We have to see how big the damage is. I don’t think it was a malicious tackle, it was a fully committed tackle. Let’s hope we get good news that [Oxlade-Chamberlain’s absence] is only two to three weeks and not six to seven.”

It is wishful thinking on Wenger’s side that Oxlade-Chamberlain will be out for just a few weeks and it is certain that he will not be available for England’s internationals against Germany and Holland on 26 and 29 March respectively.

Asked whether the player could be deprived of the opportunity of representing his country at Euro 2016, Wenger replied: “I don’t think so but I am a bit cautious because he is seeing a specialist.”

The loss of Oxlade-Chamberlain is unfortunately timed, arriving as Arsenal prepare for a trip to Manchester United for what could be the first of seven matches in 22 days across three competitions. “It is the key period,” said Wenger. “We work the whole season for this period. That is where you are really tested. It is the most interest period in the season, the period where you can show quality, nerves and desire.”

Wenger also offered his views on Friday’s presidential election at Fifa, expressing doubt the outcome will lead to the reform he considers necessary. “Uefa has presented a good candidate with [Gianni] Infantino, who I know. I don’t know the other candidates, nor do I know any programme of anybody because that has been very vague. Honestly, I don’t believe the next elections of Fifa will change a lot. We need maybe deeper changes.

“We have to restore the credibility of our organisation which is in charge of world football and that is quite a big job. Personally I have been shocked by the bad news we’ve got for months. I would say the first thing is to convince everybody, honesty and clarity in the organisation are needed. Before I never questioned any decision by Fifa, I always thought it was good. Now you have to restore credibility.”