2004-05: Played for the Djurgarden Jr. U-20 team in Sweden.
2005-06: Played for Djurgarden Jr. U-20 in Sweden, where he posted a 2.40 GAA in 18 games with a .910 save percentage. Ridderwall also earned a shutout at the elite level.
2006-07: Ridderwall was the third string goaltender for the Djurgardens IF of the Swedish Elitserien and was thus assigned the task of playing for the team’s under-20 affiliate. Making the most of his playing time, this solid goaltending prospect played in 28 games for the Djurgarden IF J20 team. The numbers he posted were astounding — a 1.78 GAA and four shutouts. And just when one thought he couldn’t play any better, in the playoffs Ridderwall brought his game to a new level, playing in seven games and recording a playoff leading 1.44 GAA and .956 save percentage. His individual efforts, unfortunately, were not enough, as his team eventually fell to Frolunda in the championship series.
2007-08: Ridderwall saw time with several Swedish teams during the 2007-08 season. He started in the under-20 league and over eight games he posted a goals against average of 1.75 and a save percentage of .934. He moved up to the elite league for 11 games, posting a 2.68 goals against average and .907 save percentage.
2008-09: In 27 games with Djurgården, Ridderwall posted a .897 Save Percentage.
2009-10: In a breakout season, Ridderwall played hot for Djurgården, in 26 games, posting a .917 Save Percentage and 2.30 GAA.