The injury occurred during Friday’s game against the Caroline Hurricanes.
Lemieux played 10:36 against the Hurricanes, but was limited to just three shifts in the final period, suggesting that the injury may have occurred in or around that point in the game.
No further specifics about what cause the fractured were revealed by the team at this time.
Lemieux has five goals and eight assists 35 games this season.
The Rangers are in action tonight against the Toronto Maple Leafs, kicking off a four-game Canadian road trip in which they will also face the Edmonton Oilers, Calgary Flames and Vancouver Canucks.