Wild forward Jason Pominville also missed Thursday's practice and will not travel to Chicago for Friday's game. He missed Game 1.
Coach Mike Yeo says if Backstrom is unable to go, Josh Harding will get the start on Friday night after he made 35 saves in Minnesota's 2-1 overtime loss in the opener Tuesday night.
Blackhawks centre Dave Bolland and goalie Ray Emery have been ruled out for Game 2 due to lower-body injuries. But Emery skated on Thursday, and coach Joel Quenneville says both players could travel to Minnesota for Game 3 on Sunday.