"He's earned the opportunity to be part of our group," Maple Leafs coach Randy Carlyle said.
Rielly, selected by the Maple Leafs with the fifth pick of the 2012 NHL Draft, has four assists and a minus-3 rating in eight games, and is averaging 18 minutes of ice time per game.
Carlyle, however, would not guarantee Rielly would remain with the team for the remainder of the season.
If Rielly plays the next two games, his 10th game would be Oct. 26 against the Pittsburgh Penguins. By playing that 10th game, the first year of Rielly's entry-level contract would go into effect. The Maple Leafs still could return him to his junior team, the Moose Jaw Warriors of the Western Hockey League, but they would waste the first year of his contract and they couldn't recall him except under emergency conditions.
Since Rielly is 19 and was drafted from a Canadian Hockey League club, he is ineligible to play in the American Hockey League.