Toronto Maple Leafs defenceman Morgan Rielly left the team's 4-3 win over the Buffalo Sabres on Tuesday night early with a suspected knee injury.

Midway through the first period, the 22-year-old defenceman fell awkwardly on his right leg after colliding with Sabres forward William Carrier as the pair reached for a puck in the Leafs' zone.

Rielly went to the dressing room after the play and attempted to resume playing, but again returned to the back. The team announced he wouldn't return just as the second period got underway.

After the game, Leafs coach Mike Babcock had no update on Rielly's status and said the team would know more on Thursday.

A native of West Vancouver, BC, Rielly has incurred a serious injury to his right knee once before in his career. In 2011-12, Rielly missed a majority of the Moose Jaw Warriors' Western Hockey League season - appearing in only 18 regular-season games - with a torn anterior cruciate ligament. He would return during the team's playoff run and go on to be taken by the Leafs with the fifth overall selection in the 2012 NHL Entry Draft.

Wednesday night was Rielly's 42nd game of the season. Rielly has a goal and 16 assists and leads the time in ice time at 22:51 a night.