Heiskanen underwent successful knee surgery in New York on Tuesday and is being labeled month-to-month, Stars radio analyst Bruce LeVine reports.

Heiskanen (knee) has been placed on injured reserve, per the NHL media site Friday.

Heiskanen (lower body) will be out of action through the 4 Nations Face-Off, Chris Johnston of The Athletic reports.

Heiskanen (lower body) underwent an MRI on Wednesday and is currently considered week-to-week, Lia Assimakopoulos of The Dallas Morning News reports Thursday.

Heiskanen scored an empty-net goal on two shots in Thursday's 4-1 win over the Flyers.

Heiskanen produced an assist, three shots on goal and a plus-2 rating in Wednesday's 5-3 loss to the Maple Leafs.

Heiskanen notched a power-play assist and three blocked shots in Monday's 2-1 win over Utah.

Heiskanen delivered a goal and an assist in Monday's 6-4 loss to the Hurricanes.

Heiskanen scored his first two goals of the season in Monday's 7-1 win over the Penguins.

Heiskanen notched two assists, including one in the power play, in Saturday's 4-2 win over the Blackhawks.