The play was a knee-on-knee collision. Foegele appeared to intentionally stick his knee out to target the Panthers forward's knee. Luostarinen's knee appears to be hyperextended on the hit, leading to a serious injury for the Panthers forward.
The referees on the ice quickly called a major penalty on the play as Leostarinen laid on the ice, clearly in a lot of pain. After a very short review, the call was confirmed and Foegele was removed from the penalty box, as the penalty comes with an automatic game misconduct.