Arsenal defender Jurrien Timber missed the Netherlands' group training session on Tuesday, raising concerns about a possible setback in his recovery. Timber has faced several injury challenges in recent years, including a groin injury that sidelined him for two months during Arsenal's successful title-winning season. He also previously returned from an ACL (anterior cruciate ligament) injury in his debut season at the Emirates, where he became one of the Premier League's top right-backs. Timber was a substitute in Arsenal's Champions League final loss to Paris Saint-Germain in May, but he wasn't deemed fit for the World Cup, which was a major disappointment for the player. Since then, Arsenal manager Mikel Arteta has been cautious with Timber's fitness. He did not take part in any of Arsenal's pre-season matches, instead focusing on individual rehabilitation during pre-season camps in Spain and the Republic of Ireland. Timber returned to London for specialist check-ups in late July and made his first appearance of the season in Arsenal's win over Sunderland, playing 60 minutes against Brighton in the following match. Netherlands head coach Xavi included Timber in the squad for the upcoming Nations League matches, and the defender is keen to play more regularly. However, his absence from Tuesday's training session sparked worries of a setback. According to Voetbal International, this was not unusual, as Timber is following an individual recovery program due to the lingering effects of his previous injuries, which also led to his exclusion from the World Cup. He is on a modified training schedule, agreed upon with Arsenal, and both the club and the Netherlands are carefully managing his workload to avoid further injury. The Netherlands' Nations League campaign begins with matches against Germany on Thursday at the Johan Cruijff Arena, followed by games against Serbia and Greece. The international break will conclude with a match against Serbia in Amsterdam on October 4. Stephen Smith, CEO and founder of Kitman Labs, emphasized the importance of managing Timber's workload to prevent a recurrence of injuries. Smith noted that Arsenal's approach of carefully managing his playing time is appropriate given his injury history and his importance to the team.