Fraser was hit by the Flyers' Jay Rosehill during a third-period scrum that started after Fraser had been called for a minor penalty for high-sticking the Flyers' Zac Rinaldo. After serving the penalty, Fraser left the penalty box and did not return to the game.
The only spare defenseman the Maple Leafs have on their roster is rookie Morgan Rielly, the fifth pick of the 2012 NHL Draft who was a healthy scratch the first two games.
The Maple Leafs next play Saturday, when they play their home-opener against the Ottawa Senators (7 p.m. ET, CBC).