Mikel Arteta has confirmed that Martin Ødegaard has sustained ligament damage in his ankle and will be out of action for an unspecified period after the Arsenal captain suffered an injury while on international duty. Ødegaard missed Arsenal's victory over Tottenham in the north London derby on Sunday, having been forced off during Norway's win against Austria last week. Initially, Arteta was hopeful that scans would reveal a less severe injury, allowing Ødegaard to return to the pitch sooner rather than later. However, the Arsenal manager disclosed before their Champions League opener against Atalanta that the 25-year-old had suffered a significant injury.

"After the scans were completed, it was revealed that he has some damage, particularly to one of the ligaments in his ankle," Arteta said. "We will miss him. I don't want to speculate on a timeline because I'm not a doctor, but it is a significant injury, so we will be without him for a while. Hopefully, it won't be months, but we'll have to wait and see."

Ødegaard did not travel with the Arsenal squad to Italy for the match against last season's Europa League winners on Thursday. However, there was some positive news as summer signing Riccardo Calafiori was deemed fit to play after returning early from international duty due to injury. Bukayo Saka is also available despite being substituted early against Spurs. Arteta acknowledged that Arsenal must adapt to playing without Ødegaard, who has only missed five Premier League matches in the past three seasons but will not be available for Sunday's clash with Manchester City at the Etihad Stadium.

"We have to demonstrate our ability to cope," Arteta said. "He is our captain and one of our most important players, without a doubt. He has been one of the most consistent performers over the last two or three seasons. Our playing style and identity are closely tied to his approach and behavior. We will have to manage without him. This is a significant test for the team, to show that we can present a different face and that we have other players and options who can still be very effective."

Arsenal lost three of their five away matches in last season's Champions League as they progressed to the knockout stages for the first time since 2017, before being eliminated by Bayern Munich in the quarter-finals. The new format has presented them with a challenging initial fixture against Gian Piero Gasperini's side, but Arteta is confident that his team will draw strength from their unbeaten away run in the Premier League, which dates back to last year.

"Hopefully, we have learned from our experiences and can demonstrate composure, determination, and belief," Arteta said. "Tomorrow, we will be ready and aware of the challenge we face, which will be tough. Hopefully, the team is prepared and ready to perform."

Arteta added: "If we aspire to reach the level we aim for, we must perform exceptionally well both away and at home. There is no alternative. We must continue to be consistent, secure results, and deliver outstanding performances that will lead to positive outcomes. Winning in Europe, like in the Premier League, is extremely difficult. Hopefully, we can be more effective than we were last season, as in this competition, small margins often determine the outcome, and we must be at our best."