2006-07: Frederik Andersen's first international recognition came in the WJC U-18 Division I B tournament. He won all four starts with a 1.25 GAA and .937 save percentage as Denmark swept through the tournament winning all five of their games. He was also chosen for Denmark's U-20 team but did not appear in any games. Domestically, he split the season between Herning's U-20 and second division men's team.
2007-2008: After once again split the domestic season between Herning's U-20 and second divison teams, Andersen's international experience was not as enjoyable as in 2006-07. Having been promoted to the WJC U-20 main draw, Denmark was frequently overmatched and Andersen and goaltending partner Christian Moeller bore the brunt of the onslaught. The Danes lost all six games in the tournament, including a 10-1 drubbing at the hands of Sweden, and Andersen finished with a 5.62 GAA and .854 save percentage.
2008-09: In first full season with Herning Blue Fox in AL Bank Ligaen (Danish top league), apppeared in 56 games with a 2.45 GAA for the Herning Blue Fox. In international play, Andersen had a decent tournament for Denmark, which had been relegated to the WJC Division I due to their poor showing the prior year. Denmark, hosting the B tournament, won its first four games but fell to Austria, 8-3, in its final game and missed an opportunity to be promoted. Andersen was in net for all but 56 seconds of the tournament and finished with a 2.01 GAA and .899 save percentage. Andersen was also named to Denmark's men's team for the World Championships but did not see any action.
2009-10: In domestic league play, Andersen finished with the top save percentage (.913) and a GAA of 2.19 in 32 regular season games for third-place Frederikshavn. Appeared in 10 playoff games for Frederishaven, which won a seven game quarterfinal series over Rodovre before falling to SonderjyskE in four straight. In ten playoff games he had a 2.86 GAA with a .925 save percentage and pulled off the rare feat of scoring a goal when he nailed an empty netter in Game 4 vs Rodovre.Playing for Denmark at the World Championships in Germany, Andersen started just two games as veteran Patrick Galbraith saw most of the action. But Anderson's first start was a game that will be talked about in Danish hockey circles for a long time as Denmark beat hockey power Finland, 4-1 despite being out-shot, 37-16. His other effort, a 6-1 loss to Russia later in the tournament, was not as memorable as the Danes faded and wound up in eighth place despite early wins over the Finns, the USA, and Slovakia.
2010-11: Andersen returned to his native Denmark, playing for Fredrikshaven, which finished third in the nine-team AL-Bank Ligaen and advanced to the playoff finals. Andersen appeared in 35 of 39 games during the regular season (second-most in the league) and had a 2.49 GAA with a .920 save percentage. In 11 playoff games, he had the second-best GAA (1.98) and the top save percentage (.942). Andersen was in net for Denmark at the 2011 IIHF World Championships and, despite his team being out-shot in all four games he started, he was 2-2 with a 3.41 GAA and .910 save percentage. In Denmark's 4-3 loss to Russia he stopped 36 of 40 shots.
2011-12: Andersen moved up to Sweden's Elitserien and was one of the league's top goalies playing for Frolunda. He had seven shutouts in 39 games and posted a 1.67 goals against and .941 save percentage. Frolunda finished fifth in the league and Andersen played all six games in the playoff series against Brynas. He finished 2-4 in the playoffs and had a 2.69 goals against and .911 save percentage. Andersen played for Denmark, which finished 13th, in the 16-team 2012 IIHF World Championship tournament. He had Denmark's only win, a 2-0 shutout of Latvia, and was 1-5 with a 3.34 goals against and .888 save percentage. Originally selected by Carolina in the seventh round in 2010 but never signed to a contract, Andersen re-entered the NHL Draft in 2012 and was selected by Anaheim in the third round (87th overall). He signed a two-year entry level contract with the Ducks in July, 2012.
2012-13: Andersen made a successful adjustment to North American hockey in his first season with Anaheim AHL affiliate Norfolk after coming over from Sweden's Elitserien. Sharing the goaltending duties with Igor Bobkov at the beginning of the season, Andersen gradually handled the lion's share of the goaltending for the Admirals. He was 24-18-1 with 4 shutouts in 47 games and had a 2.19 goals against and .929 save percentage. Norfolk was fifth in the East Division; two points out of an AHL playoff spot.
Andersen is a big goalie who fills much of the net with his frame. Though he is very raw and has not played at a high level of competition, he has the physical tools to be an effective goaltender. He was not ranked in Central Scouting's list of 10 European goalies for the 2010 draft, but scouts at the 2010 IIHF World Championship tournament in Germany were impressed with his composure and willingness to battle. He has continued to suit up for Denmark in international competition. He put up tremendous numbers in his AHL debut in 2012-13 and was arguably the Admirals most valuable player.
Andersen made the future goaltending battle in Anaheim very interesting with a fantastic rookie season in the AHL. He was among the tops in the league in both goals against and save percentage despite being on a sub-par Norfolk squad. He beat out Bobkov already and it seems like the potential for him to be at least an NHL back-up is becoming more of a reality in the near future.