Saarijarvi inked a two-year contract with Lukko (Finland) on Friday.
The Red Wings traded Saarijarvi to Arizona in exchange for goaltender Eric Comrie.
Saarijarvi will start the new season with AHL Grand Rapids, according to Red Wings coach Jeff Blashill, MLive.com reports.
Saarijarvi and fellow defenseman Filip Hronek stood out among prospects at the Red Wings development camp.
Saarijarvi, who's been participating in Detroit's development camp, said he's focused on getting stronger to complement his quickness on the ice.
Saarijarvi has seven points in his first six games for OHL Mississauga since returning from off-season wrist surgery.
The Red Wings placed Saarijarvi (wrist) on injured reserve Saturday, Ansar Khan of MLive.com reports.
Saarijarvi will undergo wrist surgery with a return timetable of three months, Mlive.com reports.
Saarijarvi, who was Detroit's third-round selection in the 2015 draft, is dealing with a minor undisclosed injury but will not require surgery, the Detroit Free Press reports.
Saarijarvi completed his season in the OHL was was reassigned to the AHL by the Red Wings.