Dahlstrom, 21, scored one goal with seven assists in 50 games this season for Linkopings HC in the Swedish Hockey League. The defenseman has spent his last three seasons with Linkopings HC.
The Stockholm, Sweden native signed an ATO with Rockford last April after registering six points (three goals and three assists) in 55 regular-season games and an assist in 11 postseason games. He tallied one assist in two games for Rockford.
The Hawks drafted Dahlstrom in the second round with the 51st overall pick in the 2013 NHL Draft.
The moves comes less than two weeks after fellow Swedish defenseman Robin Norell signed a three-year deal worth $715, 833 with Chicago. He signed an ATO with Dahlstrom last April and will be on one for the remainder of this season before his deal kicks in.
Norell, 21, recorded two goals and six assists in 51 SHL games for Djurgardens.