One of the Leafs’ top prospects’ time at development camp came to an unexpectedly early end when he suffered a concussion from an open-ice hit delivered by defenceman Nolan Dillingham.

Hirvonen was skating through the middle of the ice when the unsuspecting player got hit hard by Dillingham. The Finnish center was lying motionless on the ice and was given attention by the trainer before getting off the ice on his own power.

Hayley Wickenheiser, Leafs assistant GM, confirmed to reporters that Hirvonen received a concussion from the collision and would need some time to recover. She was quick to point out that she deemed the hit to be clean but unexpected during a summer scrimmage. On a positive note, Hirvonen was spotted walking around the Ford Performance Centre on his own accord so the outcome could have been a lot worse.

Hirvonen is fresh off a 28-point campaign with HIFK Helsinki while also adding four points in 11 playoff games. He is set to begin his first pro-season in North America with the Marlies where he is expected to spend the year in the AHL to develop his game.

He was originally taken in the second round at 59th overall in the 2020 NHL Draft.

Dillingham is a free-agent invitee who spent the past five years with the Sarnia Stings of the OHL. In his overage campaign, he captained the team and recorded 14 points in 45 games while adding six points in 12 playoff games.