The NHL is investigating how Tampa Bay Lightning forward Pontus Holmberg injured his left arm after crashing into an unlatched penalty box door during Monday's 4-2 loss to the Buffalo Sabres. The incident occurred when Holmberg, following a clean check from Peyton Krebs, fell into the penalty box door that had been left open by the operator.

Lightning coach Jon Cooper expressed frustration over the dangerous situation, suggesting the penalty box operator should be fired for leaving the door unlatched. Holmberg, who didn't return to the game, was later seen with his arm in a sling. The injury adds to Tampa Bay's mounting injury list, which already includes captain Victor Hedman on personal leave and forwards Brandon Hagel, Scott Sabourin, and Anthony Cirelli.

Cooper also criticized the officiating, citing seven minor penalties called against Buffalo and six against Tampa Bay. The teams are now tied with 102 points atop the Atlantic Division standings. The incident overshadowed what was otherwise a chippy game lacking the intensity of their previous meeting, when Buffalo rallied from a two-goal deficit to win 8-7 in a contest featuring over 100 penalty minutes.