Kings coach Darryl Sutter announced the extent of King's injury Monday.
King is a two-time Stanley Cup champion who plays a valuable depth role for Los Angeles. He had 13 goals and 13 assists for the Kings last season.
He was slated to start at left wing on the Kings' third line this season. He was hurt while blocking a shot in the Kings' final exhibition, but he still played the rest of the game.
Sutter said King is expected to be out for eight to 10 weeks.
King has 37 career NHL goals in 238 games with Los Angeles.