 During his time with Fredrikstad, Piiroja won four consecutive Estonian Player of the Year awards, in 2006, 2007, 2008 and 2009.Fredrikstad finished the 2009 season in 14th place and were relegated from the Tippeligaen after a 0–2 loss against Sarpsborg 08 in the play-offs.Fredrikstad returned to the Norwegian top division after a season, with Piiroja scoring in both legs of an 8–1 aggregate win against Hønefoss in the promotion play-offs.