He has appeared in 17 European matches, amongst others against Rubin Kazan, Napoli, Club Brugge, Legia Warsaw, Manchester United, Slovan Bratislava and FC Krasnodar.

[2] Andersen signed a loan deal with Torquay United on 26 February 2008,[3] making his debut the same day in a 1–1 draw at home to Altrincham.

In December 2008, he was again signed on an emergency loan, this time for Brentford, whose first-choice keeper Ben Hamer, also borrowed from Reading, was suspended.

[13] Andersen played all six matches in the Europa League group stage against Club Brugge, Legia Warsaw and Napoli, where FC Midtjylland finished as runners-up to qualify for the final rounds.

In February 2016, Midtjylland and Andersen beat Manchester United 2–1 at MCH Arena and lost 1–5 at Old Trafford in the second leg of round of 32.

In the same 2015–16 season, Andersen kept an average score of under one goal against in the Superliga, where Midtjylland finished third in the league and won bronze medals.

[16] On 31 August 2021, Andersen joined newly promoted Danish Superliga club Viborg FF on a deal until June 2023.

[18] On August 4, 2023, Andersen was suddenly on the team sheet and in the starting lineup when the newly relegated Danish 2nd Division club Fremad Amager met HIK in a league match.