Mikel Merino, a Spanish midfielder who recently joined Arsenal from Real Sociedad, has been ruled out for several weeks after suffering a shoulder injury during his first training session with the club. Arsenal manager Mikel Arteta confirmed the news on Friday, stating that Merino collided with a teammate during Thursday’s practice, resulting in the injury. The 28-year-old European champion with Spain this summer, joined Arsenal on Tuesday. The incident occurred during his first collective training session, where he fell and was accidentally stepped on by defender Gabriel. Arteta reported that Merino appears to have sustained a minor fracture. This injury comes as a blow to Arsenal, who are set to face Brighton on Saturday in their third Premier League match of the season.