Dahlen, 20, finished second in the Allsvenskan with 44 points (23-21-44) in 44 games. His 1.0 points per game and 0.52 goals per game led the League during the regular season. The 5-11, 176-pound forward also led all Allsvenskan players in playoff scoring with 14 points in 10 games.
In 2016.17, Dahlen registered 41 points (24-17-41) with Timra and six points (5-1-6) in seven games for Sweden at the 2017 IIHF World Junior Championship.
A native of Ostersund, Sweden, Dahlen was originally selected by Ottawa in the second round, 42nd overall, at the 2016 NHL Entry Draft. He was acquired from Ottawa in exchange for Alex Burrows on Feb. 27, 2017.