The Los Angeles Kings have activated center Derek Armstrong from the injured reserve list. Armstrong sustained a groin injury during a practice and was placed on injured reserve on November 1. The move was retroactive to October 25. The 6-foot, 190-pound center has missed four games during his absence. In 10 contests this season he has registered two goals and seven assists. In 219 career NHL games with the New York Islanders, Ottawa Senators, New York Rangers and Kings, Armstrong has recorded 101 points (37 goals, 64 assists) and 123 penalty minutes. In other roster moves, the Kings assigned Ken Belanger to the Manchester Monarchs of the American Hockey League.