Arsenal's preparations for their upcoming Premier League clash against Manchester City have been disrupted by an injury to captain Martin Odegaard. The Norwegian midfielder was forced off the pitch in the first half of their match against Nottingham Forest on Saturday, after appearing to aggravate a pre-existing shoulder problem.

Odegaard's injury occurred following a challenge involving Morgan Gibbs-White and Jurrien Timber. He landed awkwardly on his shoulder, initially tried to play through the pain, but was ultimately unable to continue. He was replaced by 18-year-old Ethan Nwaneri in the 17th minute.

This setback comes as a major blow for Arsenal, with a challenging run of fixtures ahead. They are set to face Athletic Club in their Champions League opener on Tuesday, followed by the crucial away game against Manchester City on September 21st.

Odegaard had been struggling with a shoulder issue since August, after their 5-0 victory over Leeds United. He was named on the bench against Liverpool before the international break as he was nursing the injury. However, he featured for Norway in both of their international games, even scoring in their 11-1 win against Moldova. Prior to the game against Nottingham Forest, Odegaard declared himself fit, stating he had the shoulder issue "under control" and was "ready" to play.

Arsenal manager Mikel Arteta expressed his concern after the game, stating that the injury appeared to be to the same shoulder that Odegaard had previously injured. When asked about Odegaard's availability for the Athletic Bilbao game, Arteta said that Odegaard would "be doing everything from now on to be ready," but admitted he did not know if he would be fit.

There is some positive news for Arsenal, with William Saliba returning to training following an ankle injury. However, he wasn't fully ready to start the game against Nottingham Forest. Bukayo Saka, Kai Havertz and Gabriel Jesus are already expected to miss the Champions League game.

Odegaard's potential absence would be a significant loss for Arsenal. His creativity, work rate, and leadership are vital to the team's attacking play and overall balance. If he is unable to recover in time for the Manchester City game, Arteta will have to reshuffle his midfield and find a way to compensate for his absence.