Lightning defenseman Mattias Ohlund will need arthroscopic surgery on both knees, coach Guy Boucher said Monday. The procedures will be performed on Tuesday. Ohlund could be out four to six weeks, although the team is officially saying he is out indefinitely. Ohlund, 35, who has yet to play this season, had five assists and had a plus/minus of minus-7 in 72 games last season.