Giordano, a front-runner to win the Norris Trophy as the NHL's top defenceman, was listed as out indefinitely several days ago.
With 11 goals and 37 assists for 48 points, Giordano is tied with P.K. Subban of the Montreal Canadiens for the league lead in points among defencemen.
Giordano has reportedly been sent back to Calgary, days after general manager Brad Treliving said the 31-year-old needed more evaluation.
Schlemko is a 27-year-old, left-shooting defenceman with nine goals and 41 assists in 212 career games with the Stars and Arizona Coyotes.
He has a goal and three assists in 25 games this season.