Pearson sustained the injury against the Winnipeg Jets on Saturday, when he went feet first into the boards.
Pearson, 22, and Toffoli, 22, each have 12 goals this season, which is tied for second on the team. On Sunday, Pearson was selected to the upcoming NHL All-Star Game as a rookie invite.
The Kings (19-13-10) host the Toronto Maple Leafs on Monday.
- Molly Geary