Koivu earned a roughing penalty for the hit at 3:52 of the opening period, and the Stars capitalized on the power play when Ray Whitney scored 30 seconds later.
But Fiddler did not return to the ice; he played just 1:21 before heading to the dressing room with what was termed an upper-body injury. The team said his return is questionable.
With his fourth-line center out, Stars coach Glen Gulutzan shuffled his lines considerably, putting Antoine Roussel and Tomas Vincour, who had been playing with Fiddler, on the ice in a number of different combinations.
Fiddler is one of six Stars players who have not missed a game this season. The veteran center was one of three Stars who played all 82 games in 2011-12.