Answer
Ajax appointed Vermaelen as captain after Klaas-Jan Huntelaar's departure. Vermaelen's leadership qualities and experience made him a natural choice to lead the team. He had previously served as vice-captain and had shown his dedication and commitment to the club. Under Vermaelen's captaincy, Ajax won the Eredivisie title in the 2010-11 season and reached the semi-finals of the UEFA Europa League.