Career
Aalborg BK
Andersen started playing youth football with Aalborg Freja, before moving to Aalborg BK (AaB) at the age of 10. He penned his first professional contract with AaB in September 2009. Andersen made his debut for AaB on 5 March 2011 at the age of 16 years and 174 days, making him the youngest player ever to play for AaB in the top-flight Danish Superliga championship and the second youngest player ever to play in the Danish Superliga.
Andersen was usually employed as a right winger, but was capable of playing on the left, as well as an attacking midfielder/playmaker behind the forwards.
He was touted as the most promising player to come through the AaB youth ranks since Jesper Grønkjær, by AaB director of football Lynge Jakobsen A number of foreign clubs wanted to sign him by 2012, but Lynge Jakobsen did not want to sell Andersen at too young an age. AFC Ajax
On 31 August 2012, Andersen signed with Ajax for an undisclosed fee, with a view to join the squad of Jong Ajax at first.
AaB"s good relationship with Ajax, having sold Jesper Grønkjær to Ajax as well, was emphasized by Lynge Jakobsen as a reason for the deal materializing. Andersen got his debut 8 December, coming in against Football Club Groningen, where he almost had a dream debut, hitting the post in the 90th minister
He was a part of the Denmark under-17 squad at the 2011 Union of European Football Associations European Under-17 Football Championship and the 2011 Fédération internationale de football association U-17 World Cup.
On 8 January 2012, he was called up for the Denmark League XI national football team for their matches in the 2011 King"s Cup. With his age of only 17 years and 4 months, he is the youngest player ever to have been a part of the Danish League XI squad.
