Carlyle said Friday that Lupul fell during practice Thursday and an X-ray showed a fractured bone. Lupul will wear a cast for 10 days, Carlyle said Saturday.
Lupul, an alternate captain, was sixth on the team in scoring last season with 44 points. He has three points in nine games thus far this season. He is third among Leafs forwards in average ice time.
The Leafs are sixth in the Atlantic division with 11 points (5-4-1).
- Dan Gartland