Hartnell, an All-Star last season, was injured by a shot taken by teammate Kimmo Timonen in Tuesday's game against New Jersey. Flyers general manager Paul Holmgren made the announcement before Thursday night's game against the New York Rangers.
Hartnell had one point in three games. He led the Flyers with 37 goals last season and had 67 points.
The Flyers are still without forward Danny Briere (broken left wrist). Holmgren says it's 50-50 Briere will be available for this weekend's games at Florida and Tampa Bay.
When things aren't going well for us in this city [Toronto], I think there is a lot of overanalyzing going on. You've got the most passionate fans in the world here and a lot of (media) coverage, so you know there's going to be a lot of people giving their two cents worth on us.
— Toronto Maple Leafs forward James van Riemsdyk after a win against the Tampa Bay Lightning on Thursday