Kulemin blocked a shot with his foot in practice Friday and could have played hurt for a month. Instead, the team and doctors decided to put the winger in a walking boot and not take the chance of making it worse.
"It's just a small bone broken in the ankle," Carlyle said. "To say it's not a significant injury would be incorrect. It's one of those things."
Carlyle said it was not a displaced fracture, which is why Kulemin would have been able to continue playing. But the Leafs will be without him starting Saturday night in their home opener against the Ottawa Senators.
Kulemin, 27, had two assists in the Leafs' first two games of the season.