Vlasic is questionable for Thursday's game against the Red Wings due to an illness, Scott Powers of The Athletic reports.
Vlasic didn't participate in Thursday's morning skate, and it's not yet clear whether he'll be forced to miss a game due to his illness. The 25-year-old defenseman has appeared in each of the Blackhawks' first 12 games of the regular season, recording two assists, 17 blocked shots, four hits and two PIM while averaging 20:26 of ice time.