Aged 16, Daniel and Henrik began their professional careers in 1997–98 with Modo Hockey of the Swedish Hockey League. Daniel recorded 12 points over 45 games during his rookie season. In his second professional year, he led Modo in scoring with 42 points in 50 games, helping the club to its second regular season title in team history. Daniel then added 12 points in 13 playoff games as Modo advanced to the Le Mat Trophy Finals, where they lost to Brynäs IF. At the end of the campaign, Daniel and Henrik were named co-recipients of the Golden Puck, the Swedish player of the year award.