Hartman was controlling the puck with his back to Kruger when he cocked back his left elbow and hit the Chicago veteran in the face. Kruger fell to the ice and left a trail of blood on the United Center ice as he was helped off the ice by an official with 3:29 left in the second frame. Kruger did not return for the third period.
Both Luke Johnson and Nilsson saw time at the fourth-line center spot during Kruger’s absence. Johnson and Nilsson split the four-game stint and neither one recorded a point.
Nilsson was recalled Dec. 22 after scoring four goals with two assists in his last eight games for the IceHogs. The 25-year-old, who stands at 5-foot-11 and 181 pounds, has six goals and 14 points in 31 AHL games in his first North American season. He signed a one-year contract in May after scoring eight goals and 18 points for Mora IK in Sweden last season.
The IceHogs have a home-and-home with the Chicago Wolves, starting Friday before visiting Grand Rapids on New Year’s Eve. The Blackhawks close out the 2018 calendar year Saturday against the Avalanche in Denver.